TESS Science Conference II
Aug 2 - 6 2021, Online
If you submitted an abstract and do not see it listed here, please contact us at tsc2@mit.edu with your name and your abstract information.
Use the table below to view and search abstracts or jump directly to a listing of all posters.
| Type | Author | Title | Affiliations | Abstract | |
|---|---|---|---|---|---|
| Type | Author | Title | Affiliations | Abstract |
schedule: Tuesday, 20:30 UT / 16:30 ET (invited)
Merrin Peterson & Björn Benneke
(University of Montreal)
Merrin Peterson [1], Björn Benneke [1], Karen Collins [2], Ian J. M. Crossfield [3], Caroline Piaulet [1], Mohamad Ali-Dib [1], Jessie L. Christiansen [6], Jonathan Gagne [7], David Charbonneau [2], JackieFaherty [8], Courtney Dressing [4], Felipe Murgas [10], Marion Cointepas [11], Jose Manuel Almenara [11], Xavier Bonfils [11], Stephen Kane [9], Michael W Werner [12], Varoujan Gorjian [12], Francisco J. Pozuelos Romero [13], Quentin Jay Socia [18], Lauren Weiss [17], Ryan Cloutier [2,25], Jeremy Dietrich [2], Jonathan Irwin [2], William Waalkes [20], Zach Berta-Thomson [20], Thomas Evans [3], Daniel Apai [18,19], Enric Palle [10], Norio Narita [22], Andrew W. Howard [23], Diana Dragomir [24], Khalid Barkaoui [16], Micheal Gillon [15], Emmanuel Jehin [14], Howard Isaacson [4], Alex Bixel [18], Aidan Gibbs [5], George Ricker [3], David W. Latham [2], Jose Perez Chavez [28], Avi Shporer [3], Benjamin V. Rackham [3], Thomas Henning [29], Paul Gabor [30], Wen-Ping Chen [31], Nestor Espinoza [32], Eric L. N. Jensen [33], Kevin I.Collins [34], Richard P. Schwarz [35], Dennis M. Conti [36], Gavin Wang [37], John F. Kielkopf [38], Shude Mao [39], Keith Horne [40], Ramotholo Sefako [41], Samuel N. Quinn [2], Michael Fausnaugh [3], Gabor Fuuresz [3], Thomas Barclay [26,27], and the TESS team
1 Department of Physics and Institute for Research on Exoplanets, Universite de Montreal, Montreal, QC, Canada
2 Center for Astrophysics|Harvard & Smithsonian, 60 Garden St., Cambridge, MA 02138, USA
3 Department of Physics and Kavli Institute of Astronomy, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
4 Department of Astronomy, University of California - Berkeley, Berkeley, CA, 94720, USA
5 Department of Astronomy, University of California - Los Angeles, Los Angeles, CA, 90095, USA
6 Caltech/IPAC-NASA Exoplanet Science Institute, 770 S. Wilson Ave, Pasadena, CA 91106, USA
7 Planetarium Rio Tinto Alcan and Institute for Research on Exoplanets, Universit ́e de Montreal, Montreal, QC, Canada
8 American Museum for National History, New York, NY, USA
9 Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA
10 Instituto de Astrofisica de Canarias. Via L ́actea s/n 38200, La Laguna. Canary Islands. Spain.
11 Institut de Plan ́etologie et d’Astrophysique de Grenoble, Grenoble, France
12 Jet Propulsion Lab
13 Origenes Cosmologiques et Astrophysiques, University of Li`ege, Belgium
14 Space Sciences, Technologies and Astrophysics Research (STAR), Institute, Universite de Liege,
17 University of Hawaii, Honolulu, Hawaii, USA
18 Steward Observatory, 933 N Cherry Avenue, Tucson, AZ 85721, USA
19 Department of Astronomy, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721, USA
20 Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, USA
21 NSF Graduate Research Fellow
22 The University of Tokyo, Tokyo, Japan
23 Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
24 Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
25 Banting Fellow
26 NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
27 University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
28 Texas State University, Department of Physics, 601 University Drive, San Marcos, TX 78666, USA
29 Max-Planck-Institut fur Astronomie, Konigstuhl 17, Heidelberg 69117, Germany
30 Vatican Observatory Research Group, University of Arizona, 933 N Cherry Avenue, Tucson AZ, 85721-0065, USA
31 Graduate Institute of Space Science, National Central University, Taoyuan 32001, Taiwan
32 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
33 Department of Physics & Astronomy, Swarthmore College, Swarthmore PA 19081, USA
34 George Mason University, 4400 University Drive, Fairfax, VA, 22030 USA
35 Patashnick Voorheesville Observatory, Voorheesville, NY 12186, USA
36 American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138, USA
37 Tsinghua International School, Beijing 100084, China
38 Department of Physics and Astronomy, University of Louisville, Louisville, KY 40292, USA
39 National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Road, Beijing, China
40 SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland, UK
41 South African Astronomical Observatory, P.O. Box 9, Observatory, Cape Town 7935, South Africa
(embargoed, submitted to Nature)
schedule: Monday, 14:25 UT / 10:25 ET (invited)
Laetitia Delrez
(University of Liege)
The CHEOPS consortium
Multi-transiting planetary systems around bright stars offer unique windows to comparative exoplanetology. Nu2 Lupi (HD 136352) is a naked-eye (V=5.8) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6, and 107.6 days via radial velocity monitoring with HARPS. The two inner planets (b and c) were recently found to transit by TESS, prompting us to follow up the system with CHEOPS. This led to the exciting discovery that the outer planet d is also transiting. With its bright Sun-like star, long period, and mild irradiation (~5.7 times the irradiation of Earth), Nu2 Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We measured its radius and mass to be 2.56+/-0.09 R_Earth and 8.82+/-0.94 M_Earth, respectively, and refined the properties of all three planets: planet b likely has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the Nu2 Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
schedule: Friday, 19:55 UT / 15:55 ET (invited)
Tharindu Jayasinghe
(The Ohio State University)
Krzysztof Z. Stanek, Todd A. Thompson, Christopher S. Kochanek, Dominick M. Rowan, Patrick J. Vallely, and David V. Martin (The Ohio State University)
Our knowledge of compact object binaries is very biased. Historically, we have only identified them if they are accreting in mass transfer systems, contain pulsars or through the gravitational waves from merging systems. To fully understand their numbers, properties, formation mechanisms and evolutionary paths, new discoveries of non-interacting compact binaries are necessary. We discovered the closest known black hole candidate as a binary companion to V723 Mon. V723 Mon is a nearby (~460 pc), bright (V~8.3 mag), evolved (T_eff~4440 K, and L~173 L☉) red giant in a high mass function, f(M)=1.72 ± 0.01 M☉, nearly circular binary (P~59.9 days, e~0). V723 Mon has previously been classified as an eclipsing binary, but its ASAS, KELT, and TESS light curves are those of a nearly edge-on ellipsoidal variable. Detailed models of the light curves constrained by the period, radial velocities and stellar temperature give an inclination of 87.0±2°, a mass ratio of q=0.33 ± 0.02, a companion mass of M_comp=3.04 ± 0.06 M☉, the radius of the giant as R=24.9 ± 0.7 R☉, and the giant’s mass as M_giant=1.00 ± 0.07 M☉. The simplest explanation for the massive companion is a single compact object, most likely a black hole in the "mass gap".
schedule: Wednesday, 13:00 UT / 09:00 ET (invited)
Trevor Dorn-Wallenstein
(University of Washington)
Emily M. Levesque (1), Kathryn F. Neugent (1, 2), James R. A. Davenport (1), Brett M. Morris (3), Keyan Gootkin (1)
(1): University of Washington Astronomy Department
(2): Lowell Observatory
(3): Center for Space and Habitability, University of Bern
Massive stars drive the radiative, chemical, and kinematic evolution of their host galaxies. Despite the importance of these stars, the physical factors that govern their progression through the exotic evolved states that we observe them in are poorly understood. Thanks to TESS, high-quality light curves of massive stars in their evolved stages are revealing never-before-seen phenomena that may help answer our most urgent questions. In this talk, I will discuss the two “flavors” of variability revealed by TESS in cool supergiants and how they impact our understanding of massive stellar evolution: Stochastic low frequency variability (SLFV) previously known to exist in O and B stars appears to be ubiquitous across the upper HR-diagram. Simultaneously, we have found a new class of variable yellow supergiants that pulsate with frequencies above ~1 d^-1. Both of these discoveries open the intriguing possibility of probing the interiors of massive stars in their final phases before core collapse. Finally, I will highlight our ongoing work coupling TESS data with high resolution spectroscopy to determine the nature of SLFV in cool supergiants.
schedule: Thursday, 13:50 UT / 09:50 ET (invited)
Jeroen Audenaert
(Institute of Astronomy, KU Leuven)
Audenaert, J.
Institute of Astronomy, KU Leuven
Kuszlewicz, J. S.
Landessternwarte, Zentrum für Astronomie der Universität Heidelberg
Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University
Handberg, R.
Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University
Tkachenko, A.
Institute of Astronomy, KU Leuven
Armstrong, D.
Department of Physics, University of Warwick
Centre for Exoplanets and Habitability, University of Warwick
Hon, M.
Institute for Astronomy, University of Hawaiʻi
School of Physics, The University of New South Wales
Kgoadi, R.
College of Science and Engineering, James Cook University
Bell, K. J.
DIRAC Institute, Department of Astronomy, University of Washington
NSF Astronomy and Astrophysics Postdoctoral Fellow
Buzasi, D.
Department of Chemistry and Physics, Florida Gulf Coast University
Aerts, C.
Institute of Astronomy, KU Leuven
Department of Astrophysics, IMAPP, Radboud University Nijmegen
Max Planck Institute for Astronomy
The TESS Data for Asteroseismology working group has created a stellar variability classification pipeline to automatically classify the tens of millions of stars observed by the NASA TESS mission down to a magnitude of 15. The overall strategy of the pipeline consists in training multiple distinct supervised classifiers with different learning algorithms and features, and then combine their predictions into a metaclassifier to make the final classification. This way the metaclassifier can leverage the specific strengths of each classifier and find the correlations across the different classifiers to come to an optimal prediction. We have successfully validated our pipeline by applying it to a labelled set of Kepler Q9 data and to the 167,000 stars in Q9. In this contribution, we will present the method and its validation on the Kepler data, as well as the detailed plan for the knowledge transfer to the TESS dataset.
schedule: Monday, 19:55 UT / 15:55 ET (invited)
Patrick Vallely
(The Ohio State University)
Vallely, P. J. (OSU); Kochanek, C. S. (OSU); Stanek, K. Z. (OSU) ; Fausnaugh, M. (MIT); Shappee, B. J. (Hawaii)
We present TESS observations of twenty bright core-collapse supernovae with peak magnitudes brighter than 18 mag. Existing semi-analytic models fit the light curves of the Type II supernovae well, but do not yield reasonable estimates of the progenitor radius or explosion energy, likely because they are derived for use with ultraviolet observations while TESS observes in the near-infrared. Fitting the data instead with numerically simulated light curves, the rising light curves of the Type II supernovae are consistent with the explosions of red supergiants and the radius distribution is comparable to what is observed in the Milky Way. While we do not identify shock breakout emission for any individual event, when we combine the fit residuals of the Type II supernovae in our sample, we do find a greater than 5-sigma flux excess in the ~1 day before the start of the light-curve rise. It is likely that this excess is due to shock breakout emission, and that during its extended mission TESS will observe a Type II supernova bright enough for this signal to be detected directly.
schedule: Monday, 14:40 UT / 10:40 ET
François Bouchy
(Geneva Observatory )
F. Bouchy, F. Pepe, C. Lovis and the ESPRESSO consortium
TESS follow-up efforts using high-precision spectrographs are successfully underway to characterize transiting planets with radii below 4 Rearth. The highly-stabilized and high-resolution spectrograph ESPRESSO has been in operation at ESO/VLT since September 2019. Its 2-magnitude gain and improved radial velocity precision with respect to HARPS-like instruments allows a in-depth exploration of the rocky and mini-Neptune population detected by TESS. We will give an overview of TESS low-mass planets characterized so far with ESPRESSO-GTO program which focuses on exoplanets smaller than 2 Rearth and sub-Neptunes with stellar irradiation between 50x and 200x Earth’s irradiation. We will also present preliminary results on the program focused on mini-Neptune candidates with relatively weak stellar irradiation or long orbital periods which are not expected to experience intense irradiation or strong tidal forces.
schedule: Wednesday, 21:45 UT / 17:45 ET
David Ciardi
(NASA)
Steve B. Howell (NASA) & Elise Furlan (NASA Exoplanet Archive)
It is well established that about one-half of FGK exoplanet host stars are in binary star systems with bound companions often within 0.5” or less. ``Third-light” flux contamination dilutes the transit signal, leading to underestimated planetary radii and has implications for both planet and stellar properties. High-resolution imaging observations, using speckle interferometric instruments at the Gemini North and South 8-m telescopes, provide spatial resolutions of a few to several 100 au and contrast limits of 5 to 9 magnitudes for the majority of TESS host stars. We have observed ~600 TESS exoplanet host stars with angular and contrast limits that are not plagued, as other studies have been, by incompleteness at the closest separations. We found that exoplanet host binaries have a mean orbital separation greater than that of field stars and binary host stars show a strong observational bias against the detection of Earth-size planet transits. A situation leading to highly incorrect occurrence rates for rocky planets, especially those in longer period, habitable zone orbits. We will review the progress of this work and present information to extend the understanding of exoplanetary detection, formation, dynamics and evolution.
schedule: Wednesday, 20:20 UT / 16:20 ET
Christopher P Wirth
(Harvard University, Harvard-Smithsonian Center for Astrophysics)
George Zhou: USQ, CfA
Sam Quinn: CfA
The orbital obliquity of a young planet is a useful tracer of the system’s formation and migration history, and a large number of these measurements could help us understand the mechanisms shaping and moving exoplanets. TOI-942 is a young (about 60 Myr) planetary system identified last year, with two Neptune-sized planets in 4.3-day and 10.1-day orbits. We observed two partial transits of the inner planet, TOI-942b, using the Planet Finder Spectrograph, and used the Rossiter-McLaughlin effect to measure the projected orbital obliquity. Combining this with TESS light curve data, we determined the true orbital obliquity of TOI-942b. This is one of the youngest planets to have its obliquity characterized, and one of even fewer residing in a multi-planet system. I will discuss the TOI-942 system in the context of other young planetary systems that have been characterized, and their implications on the evolution of exoplanetary architectures.
schedule: Wednesday, 21:15 UT / 17:15 ET
Matthew Battley
(University of Warwick)
Michelle Kunimoto (Massachusetts Institute of Technology), David Armstrong (University of Warwick), Don Pollacco (University of Warwick)
The Kepler field proved to be transformational for the exoplanet community, resulting in over 2000 confirmed transiting exoplanets and redefining what is ‘normal’ for an exoplanet. In year two of its primary mission, the Transiting Exoplanet Survey Satellite (TESS) returned to the Kepler field, offering key re-observations of interesting systems which had not been re-observed from space for seven years. Here we present results from TESS observations of the Kepler field, including a direct comparison between Kepler and TESS photometry for known exoplanets and updated ephemerides for 22 Kepler planets and 4 Kepler candidates. This constitutes all Kepler planets and candidates with sufficient signal to noise in the TESS 2min dataset to allow for updated ephemerides. We also present a series of interesting O-C diagrams for the re-observed systems, alongside the results for new TTV fits of five known multi-planet systems with significant TTVs (Kepler-18, Kepler-25, Kepler-51, Kepler-89, and Kepler-396). Through this analysis, TESS has again shown itself to be an incredibly powerful instrument for exoplanet follow-up as well as a prolific planet-finder in its own right.
schedule: Tuesday, 15:05 UT / 11:05 ET
Jessica Luna
(University of Texas at Austin)
Brendan Bowler, University of Texas at Austin
Bill Cochran, University of Texas at Austin
Adam Kraus, University of Texas at Austin
Danny Krolikowski, University of Texas at Austin
Michael Gully-Santiago, University of Texas at Austin
Suvrath Mahadevan, Penn State University
Caroline Morley, University of Texas at Austin
Joe Ninan, Penn State University
Gudmundur Stefansson, Princeton University
Quang Tran, University of Texas at Austin
Andrew Vanderburg, University of Wisconson-Madison
The helium triplet at 10830 Åm lends evidence for atmospheric escape from transiting planets. This feature has been detected in planets from Neptune-mass to Jupiter-mass; to date, it has been observed for planets orbiting active stars with sufficient short-𝞴 EUV photons to populate the excited energy levels that generate this absorption feature. TESS is rapidly finding new transiting planets, the brightest being some of the best targets, to measure escaping helium exospheres. We measure the strength of the helium 10830 Åm feature during and outside of transit for a range of exoplanets using the Habitable-Zone Planet Finder (HPF) spectrograph on the Hobby-Eberly Telescope (HET) at McDonald Observatory, intending to detect escaping helium from their atmospheres. We present a proof of concept that the HPF at HET serves as an instrument to detect escaping helium atmospheres by detecting WASP-69b’s known helium exosphere (Nortmann+18). We present analysis of our large survey, including 2 new planets discovered by TESS, to measure excess helium absorption during transit for planets with a range of surface gravities, host stellar spectra, sizes, and ages to test the effect they have on helium loss and inferred atmospheric escape rates.
schedule: Wednesday, 21:00 UT / 17:00 ET
Andrew Vanderburg
(University of Wisconsin-Madison)
White dwarfs are the end-states of most stars known to host exoplanets today, but we know precious little about the fate of planetary systems after stellar death. We are using the TESS mission to address this gap in knowledge by searching for planetary systems transiting white dwarf stars. Despite the white dwarf stars' intrinsic faintness, TESS can efficiently survey many more white dwarfs than previous searches thanks to its high duty cycle, fast sampling, and wide field of view. I will present results from this search, including the discovery of a giant planet candidate transiting the white dwarf WD 1856+534 b.
schedule: Monday, 15:25 UT / 11:25 ET
Karen Alicia Collins
(Center for Astrophysics | Harvard & Smithsonian)
The TESS Follow-up Observing Program (TFOP) Sub Group 1 (SG1) team conducts TESS transit follow-up photometry for the TFOP community. For transits deeper than ~700 ppm, the primary goal is to confirm the transit on the target, or to identify an off-target source responsible for the TESS detection. For transits shallower than ~700 ppm, the primary goal is to measure the light curves of neighboring stars to rule out or identify off-target sources that could be responsible for the TESS detection. For transits confirmed on target, we often measure transit depths across multiple optical bands, which can increase confidence in the planetary nature of the TOI, or may provide evidence of a false positive. For interesting TTV systems, we conduct long-term transit timing measurements. The SG1 reduced data products often result in a multitude of files available on ExoFOP-TESS. In this presentation, I will describe how to quickly understand the current disposition of a TOI and how to quickly interpret the SG1 reduced data products available on ExoFOP-TESS. I will also describe how to extract SG1 transit follow-up photometry from ExoFOP-TESS for inclusion in the joint modelling effort for your TESS paper.
schedule: Tuesday, 15:20 UT / 11:20 ET
Vardan Adibekyan
(The Instituto de Astrofísica e Ciências do Espaço (IA))
Caroline Dorn, Sérgio G. Sousa, Nuno C. Santos, Bertram Bitsch, Garik Israelian, Christoph Mordasini, et al
Because of their common origin, it is expected (or assumed) that the composition of planet building blocks should (to a first order) correlate with stellar atmospheric composition, especially for refractory elements. In fact, information on the relative abundance of refractory and major rock-forming elements such as Fe, Mg, Si are commonly used to improve interior estimates for terrestrial planets (e.g. Dorn et al. 2015; Unterborn et al. 2016) and has even been used to estimate planet composition in different galactic populations (Santos et al. 2017). However, there is no direct observational evidence for the aforementioned expectation/assumption and was even recently questioned by Plotnykov & Valencia (2020). By using the largest possible sample of precisely characterized low-mass planets and their host stars, we show that the composition of the planet building blocks indeed correlates with the properties of the rocky planets. We also find that on average the iron-mass fraction of planets is higher than that of the primordial values, owing to the disk-chemistry and planet formation processes. This result can bring important implications for the future modelling of exoplanet composition.
schedule: Tuesday, 21:15 UT / 17:15 ET
Joseph Murphy
(University of California, Santa Cruz)
The TESS-Keck Survey team members (UC Santa Cruz, UC Berkeley, UCLA, UC Riverside, UC Irvine, University of Hawai'i, University of Kansas, California Institute of Technology)
The TESS-Keck Survey (TKS) is a large, multi-semester Doppler survey of promising planet candidates from NASA’s ongoing TESS mission. TKS is actively monitoring close to 100 TESS systems with Keck-HIRES in pursuit of key questions in exoplanet astronomy across four broad science themes: bulk planet composition, system architectures, evolved systems, and the characterization of exoplanet atmospheres. Precise planet mass measurements (> 5-sigma) are the critical first step in the interpretation of transmission spectra of small planets, as most absorption features are proportional to the atmospheric scale height which depends on both mass (surface gravity) and composition (atmospheric mean molecular weight). One of the lasting contributions from TKS will be the precise masses of ~20 sub-Neptune-size planets spanning a range of radii, orbital periods, and host star properties. In this talk, we describe the TKS selection function for atmospheric targets and summarize the survey’s preliminary results. One of the key insights from our observations is that sub-Neptunes orbiting G dwarfs have emerged as a promising population for basing a demographic study of exoplanet atmospheres with JWST.
schedule: Monday, 14:55 UT / 10:55 ET
Julia Venturini
(International Space Science Institute)
Octavio Guilera (CONICET-UNLP), Jonas Haldemann (University of Bern), Paula Ronco (Universidad Catolica de Chile), Christoph Mordasini (University of Bern)
The existence of a radius valley in the Kepler size distribution, which separates super-Earths from mini-Neptunes, stands as one of the most important observational constraints to understand the origin and composition of exoplanets with radii between that of Earth and Neptune. We provide insights into the existence of the radius valley from, first, a pure formation point of view, and second, a combined formation-evolution model. Our simulations include the evolution of dust by coagulation, drift and fragmentation; and the evolution of the gaseous disc by viscous accretion and photoevaporation. A planet grows from a moon-mass embryo by either silicate or icy pebble accretion, depending on its position with respect to the water ice line. We include gas accretion, type-I/II migration and photoevaporation driven mass-loss after formation. We find that while the first peak of the Kepler size distribution is undoubtedly populated by bare rocky cores, the second peak tends to be composed by half-rock/half-water planets with thin or non-existent H-He atmospheres.
schedule: Wednesday, 20:35 UT / 16:35 ET
Nardiello Domenico
(Laboratoire d'Astrophysique de Marseille)
The accurate knowledge of the ages of stars hosting planets allows us to obtain an overview on the evolution of exoplanets and understand the mechanisms affecting their life. The measurement of the ages of stars in the Galaxy is usually affected by large uncertainties; an exception are the stellar clusters: for their coeval members, born at the same time from the same molecular cloud, ages can be measured with extreme accuracy through the use of theoretical models. In this context, the aim of the project PATHOS is the finding and characterization of candidate exoplanets orbiting members in stellar clusters and associations by using TESS high-precision light curves obtained with appropriate cutting-edge tools. In this talk, the most important results obtained in the first two years of the PATHOS project will be presented: a particular attention will be dedicated to the frequency of candidate exoplanets around stellar clusters' members and to the relationship between stellar age and planetary radius. Also, important results regarding stellar variability in youthful associations (<10 Myr) obtained with TESS light curves will be illustrated.
schedule: Wednesday, 21:30 UT / 17:30 ET
Ashley Chontos
(Institute for Astronomy, University of Hawai'i at Mānoa)
Daniel Huber, Institute for Astronomy, University of Hawai'i at Mānoa
The subgiant branch is a rapid phase of stellar evolution, which allows the precise determination of fundamental properties of stars and the planets that orbit them. The unique age constraint in combination with the precise properties of a quickly-evolving system also makes this population of planets an ideal sample to test and constrain timescales for the dynamical evolution of planets. Here we present a homogeneous population of TESS planets orbiting subgiant stars that have been extensively followed up with Keck/HIRES. The sample comprises more than 20 TESS planets ranging from sub-Neptunes to gas giant planets, including new non-transiting planets, with precisely measured ages, densities and orbital properties. We use the sample to investigate dynamical timescales for processes such as orbital period decay, which is expected to occur faster than circularization, thus producing a transient population of mildly eccentric planets. With host star masses ranging from ~1-1.8 Msun, we also explore correlations of bulk planet properties with stellar mass and metallicity.
schedule: Tuesday, 21:30 UT / 17:30 ET
Madison Brady
(University of Chicago)
MAROON-X is a new spectrograph at the 8-meter Gemini North telescope, designed to perform extreme-precision (30 cm/s) radial velocity measurements of late-type stars. This precision allows us to observe the faint RV signatures of terrestrial planets. With MAROON-X, we have already been able to precisely measure the masses of the TESS-discovered Gl 486b and LTT 1445Ab, both of which are JWST Cycle 1 targets. We are currently using this exciting new instrument to perform a volume-limited (d < 30 pc) RV survey of TESS transiting planet candidates around M dwarfs. Here we will present a status update of this project, including new planetary masses measured over the past year.
schedule: Tuesday, 14:35 UT / 10:35 ET
Michael Gully-Santiago
(The University of Texas at Austin)
Caroline Morley (UT Austin), Will Best (UT Austin), Yifan Zhou (UT Austin), Brendan Bowler (UT Austin)
Condensate clouds should pervade the atmospheres of brown dwarfs and exoplanets, dictating the energy balance of these substellar objects and controlling their photometric and spectroscopic properties. Yet physical understanding of these clouds has largely been limited to coarse phenomenology: clouds are difficult to model and even more difficult to observe, owing to the absence of prominent spectral features and the intrinsic low luminosity of ultracool LT dwarfs. Here we present high resolution near-IR echelle spectra from IGRINS taken contemporaneously with TESS Sector 36 to quantify brown dwarf cloud modulation of Luhman 16AB, an exemplar L-T transition binary residing 2 pc from the Sun. The Sector 10, 36, and 37 lightcurves show conspicuous 10% peak-to-valley modulations arising from longitudinal asymmetries of cloud coverage, with rich harmonics suggestive of surface structures. The four epochs of IGRINS spectra sample both high and low states of cloud coverage of the B component, exhibiting wide agreement with custom cloudy synthetic grid models. We animate conceivable dynamic surface structures consistent with these two precision datasets.
schedule: Monday, 14:00 UT / 10:00 ET
Natalia Guerrero
(MIT)
We present over 3,000 exoplanet candidates discovered in the first year of the extended mission and two-year prime mission of the Transiting Exoplanet Survey Satellite. We describe updates to the process used to identify TOIs, investigate the characteristics of the new planet candidates, and highlight some notable TESS discoveries. The TESS Objects of Interest (TOI) Catalog includes both new planet candidates found by TESS and previously-known planets recovered by TESS observations. Nearly 200 TOIs are part of multi-planet systems and hundreds of TOIs are small planet candidates around nearby bright stars. TOIs provide a diverse set of system architectures and planet parameters well-suited for detailed follow-up observations.
schedule: Tuesday, 14:50 UT / 10:50 ET
Katharine Hesse
(MIT)
Michelle Kunimoto (MIT), Ismael Mireles (University of New Mexico), Natalia Guerrero (MIT)
The hot Neptunian desert refers to the lack of Neptune-sized planets (~2 Re < Rp < ~9 Re) orbiting close to their stars (P < ~5 days) typically expected in exoplanet populations. This scarcity was predicted by population synthesis models due to the inability of gas giants below Jupiter size to hold onto volatile materials in close proximity to their stars but was unsupported by radial velocity surveys. However, the exoplanet distribution from Kepler does support the existence of this desert, with less than ten percent of confirmed planets and planet candidates falling into this radius and period range. A similar disparity exists in TESS with less than fifteen percent of planet candidates located in this short period Neptune range, although there are already a few TESS confirmed planets that fit the hot Neptune profile such as LTT 9779 b. As more candidates are found and confirmed, TESS will continue to populate the Hot Neptune Desert and help explain the formation and evolution of these objects.
schedule: Monday, 15:10 UT / 11:10 ET
Nora Eisner
(University of Oxford)
Oscar Barragan (University of Oxford), Suzanne Aigrain (University of Oxford), Chris Lintott (University of Oxford), Belinda Nicholson (University of Oxford) & the Zooniverse team
I will present results from the Planet Hunters TESS (PHT) project, which harnesses the power of citizen science to find transit events in the TESS data by engaging tens of thousands of volunteers. To date, PHT citizen scientists have classified all two-minute cadence TESS data up to sector 35 and discovered over 100 planet candidates that weren't previously known. Most are long-period planets, but we also identify a wide range of other interesting planet and stellar systems. Our results show that humans can outperform the automated detection pipelines for certain types of transits, especially single (long-period) transits, as well as aperiodic transits (circumbinary planets) and planets around rapidly rotating, active (young systems), or otherwise variable stars. I will give an overview of our detection and vetting process, and show how our findings complement the population of planets identified by automated algorithms. Finally, I will present our most recent discovery, a system of two planets around the bright star HD 152843, which has outstanding prospects for atmospheric characterisation.
schedule: Tuesday, 20:45 UT / 16:45 ET
Rodrigo Díaz
(Universidad de San Martín / ICAS)
Nicola Astudillo-Defru (Universidad Católica de la Santísima Concepción, Chile)
Xavier Bonfils (Université Grenoble Alpes, France)
Jose-Manuel Almenara (Université Grenoble Alpes, France)
Xavier Delfosse (Université Grenoble Alpes, France)
Thierry Forveille (Université Grenoble Alpes, France)
Paula Gorrini (Universidad de Concepción, Chile)
Ronald Mennickent (Universidad de Concepción, Chile)
Nicolas Unger (University of Geneva, Switzerland)
Stephane Udry (University of Geneva, Switzerland)
and the ExTrA team
The planet LHS 3844 b is an ultra short-period (USP) Earth-size planet orbiting a nearby (15 pc) M dwarf. Because of the brightness of the host star (Kmag = 9.1), the planet has raised a lot of attention. The lack of a thick atmosphere has already been determined using phase curves obtained from space, and the planet is scheduled to be observed during Cycle 1 of the James Webb Space Telescope. A complete characterisation of this planet, in particular the measurement of its mass, and the detection of additional planets in the system are important steps in understanding the formation and evolution of this target. They will also help in interpreting the future observations obtained from space. Here, we report the analysis of radial velocities of LHS 3844 measured by the ESPRESSO spectrograph at the Very Large Telescope. The data allow us to determine the mass of the USP planet with a precision of around 10%, and shed light on the presence of additional companions. We present the details of the velocity analysis and announce the mass and density of the USP planet as well as the results of the Bayesian model comparison between models with different numbers of periodic signals.
schedule: Tuesday, 21:45 UT / 17:45 ET
Tianjun Gan
(Tsinghua University)
Megan Bedell (Flatiron Institute), Sharon Xuesong Wang (Tsinghua University), Shude Mao (Tsinghua University), Karen Collins (Harvard & Smithsonian), Avi Shporer (Massachusetts Institute of Technology)
The Sun has been previously found to have a depletion in refractory elements compared to the volatile elements with respect to most nearby solar analogs. Previous studies show that this deficiency feature could be linked to the rocky body and giant planet formation, galactic chemical evolution as well as planet engulfment. However, it is still unclear which is the dominant reason due to the lack of well-characterized solar twins with known planets around. As a whole sky survey, TESS presents an exciting opportunity to build a sample to further study the solar depletion pattern. In this presentation, I will report the recent detection of a warm sub-Neptune around the solar twin HD 183579. The spectroscopic abundance analysis shows that HD 183579 does not show depletion of refractory elements as our Sun, despite both having rocky bodies. By studying the solar analogs hosting confirmed rocky planets in the California-Kepler Survey (CKS) sample, we also find a similar conclusion. It hints that rocky body formation may not be the key reason to the depletion feature we saw in our Sun. I will briefly overview the aforementioned four hypotheses and summarize of our new findings.
schedule: Tuesday, 21:00 UT / 17:00 ET
Akanksha Khandelwal
(Physical Research Laboratory, India)
Akanksha Khandelwal, PRL, India
Priyanka Chaturvedi, TLS, Tautenburg, Germany
Abhijit Chakraborty, PRL, India
Rishikesh Sharma, PRL, India
Based on precise radial velocities (RVs) from the two spectrographs, PARAS at PRL, India, and TCES, Tautenburg, Germany, we report the detection of a hot Jupiter at an orbital period of 3.2087 days around TOI-1789 (TIC ID 172518755). TOI-1789 is a 9.1 TESS magnitude F-type star with an effective temperature of about 6000 K. The mass measured for TOI-1789b from the radial velocity semi-amplitude of 77±18 m/s is 0.76±0.17 MJ. We compliment the space-based TESS data with several ground-based transit observations using PRL’s 43-cm telescope in the R-band at the Gurushikhar Observatory. With the simultaneous fitting of the multiple light curves and the RV data, we measure the planet radius of 1.40^+0.14_−0.11 RJ and a density of 0.34^+0.13_−0.11 g/cm3. This puts TOI-1789b in the category of inflated hot Jupiters, which makes it a suitable candidate for atmospheric studies via transmission spectroscopy, an important addition in improving our understanding of studying inflation mechanisms in hot Jupiters.
schedule: Tuesday, 13:40 UT / 09:40 ET
Simon J. Murphy
(University of Sydney)
Meridith Joyce (ANU, Australia)
Tim Bedding (USyd, Australia)
Tim White (USyd, Australia)
Mihkel Kama (UCL, UK)
The early evolution of a star is intertwined with that of its planets and protoplanetary disk. Recent results reveal that some stellar chemical peculiarities arise from separation of dust from gas in planet-forming disks. Thus stellar composition build-up is linked to planet formation and disk evolution, but many aspects of this remain unclear. Disk evolution is thought to be rapid (3—5 Myr timescales), but age estimates have previously relied upon the ages of stellar associations, which can be unreliable because of age dispersion within associations and episodic accretion. Hence, the ages and intrinsic metallicities of protoplanetary disks are rarely known precisely.
I will discuss recent results for the pre-main-sequence star HD139614, where we use stellar pulsations to determine an age to better than 10% precision. I will describe the evolution of pulsation frequencies in pre-main-sequence stars and how this allows masses and metallicities to be determined in a degeneracy-free way, permitting stellar associations to be dated with much better precision. Finally, I will explain how a planet-forming disk has resulted in this star being chemically peculiar.
schedule: Tuesday, 13:25 UT / 09:25 ET
Dominic M. Bowman
(Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium)
Siemen Burssens (Institute of Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium)
Sergio Simón-Díaz (Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain)
Most massive stars end their lives as energetic supernovae and form a black hole or neutron star, which are strong drivers of galactic evolution. However the interior physics of massive stars, such as mixing and rotation, is not well known even during the main sequence phase of stellar evolution. Asteroseismology of gravity waves provides a unique way of probing beneath a star's opaque surface. Massive stars exhibit gravity waves excited from core convection and turbulent pressure fluctuations in their near-surface layers, which in turn produce an efficient mixing mechanism inside stars. Here we present the recent results on combining high-precision TESS photometry and high-resolution spectroscopy of massive stars. A clear relationship is found between the location of massive stars in the Hertzsprung-Russell diagram and the amplitudes and frequencies of stochastic photometric variability caused by gravity waves in their light curves. The common variability discovered in TESS photometry is strong evidence for gravity waves being a plausible mechanism for macroturbulence in massive stars, as gravity waves are unique in providing the dominant tangential velocity field required to explain macroturbulence.
schedule: Friday, 20:10 UT / 16:10 ET
Daniel Huber
(University of Hawaii)
Tim White (University of Sydney), Travis Metcalfe (White Dwarf Research Corporation), Ashley Chontos (University of Hawaii), Cynthia Ho (University College London), Vincent Van Eylen (University College London) and TASC Workings Groups 1 & 2
I will present a systematic analysis of the first 20-second cadence light curves obtained by the TESS extended mission. The data show a strong magnitude-dependent increase in photometric precision compared to 2-minute cadence data, and I will discuss two early science results enabled by this improvement. First, we use asteroseismology of bright solar analogs to find evidence that the spread in the stellar age-activity relation is linked to stellar mass and thus convection zone depth. Second, we combine 20-second data and radial velocities to re-characterize pi Men c, which is now the closest transiting exoplanet for which a detailed asteroseismic characterization of the host star is possible. The results show that pi Men c sits at the upper edge of the planet radius valley for its orbital period, confirming that it has likely retained a volatile atmosphere and that the "asteroseismic radius valley" remains devoid of planets. Our analysis also strongly favors a circular orbit for pi Men c, suggesting efficient tidal dissipation if it formed via high-eccentricity migration. Combined, the early results demonstrate the extraordinary potential of TESS 20-second cadence data for stellar astrophysics and exoplanet science.
schedule: Wednesday, 21:00 UT / 17:00 ET
Marc Hon
(University of Hawai'i)
Daniel Huber (University of Hawai`i)
James S. Kuszlewicz (Universität Heidelberg)
Dennis Stello (UNSW Sydney)
Jamie Tayar (University of Hawai`i)
Joel C. Zinn (American Museum of Natural History)
Mathieu Vrard (The Ohio State University)
Marc H. Pinsonneault (The Ohio State University)
We present the first near all-sky yield of oscillating red giants from the TESS's prime mission. We systematically detect 129,323 oscillating giants across all light curves in the MIT Quick-Look Pipeline's first data release, which is interpreted as the an approximate lower bound to the possible total yield of oscillating giants from the first two years of TESS. By combining our seismic measurements with Gaia parallaxes, we present an unprecedented near all-sky Gaia-asteroseismology mass map. Moreover, we examine the spatial, kinematic, and chemical properties of our red giant sample to demonstrate the strong potential of TESS asteroseismology for studies of the Galaxy even with only one month of observations.
schedule: Wednesday, 13:15 UT / 09:15 ET
Ingrid Pelisoli
(University of Warwick)
P. Neunteufel (MPA-Garching), S. Geier (University of Potsdam), T. Kupfer (Texas Tech University), U. Heber (University of Bamberg), A. Irrgang (University of Bamberg), D. Schneider (University of Bamberg), A. Bastian (University of Potsdam), J. van Roestel (Caltech), V. Schaffenroth (University of Potsdam), B. N. Barlow (High Point University)
Supernova Ia are bright explosive events that can be used to estimate cosmological distances, allowing us to study the expansion of the Universe. They are understood to result from a thermonuclear detonation in a white dwarf that formed from the exhausted core of a star more massive than the Sun. However, the possible progenitor channels leading to an explosion are a long-standing debate, limiting the precision and accuracy of supernova Ia as distance indicators. In this talk, we will present HD 265435, a binary system discovered by TESS with an orbital period of less than a hundred minutes, consisting of a white dwarf and a hot subdwarf — a stripped core-helium burning star. The total mass of the system is 1.65±0.25 solar-masses, exceeding the Chandrasekhar limit. The system will merge due to gravitational wave emission in 70 million years, likely triggering a supernova Ia event. We used this detection to place constraints on the contribution of hot subdwarf-white dwarf binaries to supernova Ia progenitors.
schedule: Wednesday, 21:15 UT / 17:15 ET
Ted Mackereth
(University of Toronto)
Andrea Miglio (University of Bologna), Yvonne Elsworth (University of Birmingham), Benoit Mosser (Observatoire de Paris), Savita Mathur (IAC, Tenerife), Rafael Garcia (University Paris-Saclay), Domenico Nardiello (INAF, Padova)
The advent of space-based long-duration photometry of stars has brought about a revolution in our constraints on models of stellar structure and evolution. Not only that, but it has triggered a new era of high precision stellar parameter estimation, affording mass and, therefore, age estimates for large numbers of giant stars, whose ages have long been difficult to pin down, but are readily observable over large regions of the Milky Way. In this talk, I will present a new catalogue of ~5,500 red giants in the southern TESS-CVZ, whose seismic parameters, measured from TESS light curves have afforded high quality mass and age estimates. I will show how the TESS data, in combination with constraints from Gaia and other spectra-photometric data, allows relatively precise seismic measurements albeit with shorter duration and noisier data than Kepler. I will show that even at reduced precision in age, a large all-sky TESS data-set, informed by this more detailed data in the TESS-CVZ, will be able to provide important constraints on the stellar populations of the Milky Way.
schedule: Friday, 20:50 UT / 16:50 ET
J M Joel Ong
(Yale University)
M. Lund (Aarhus)
Sarbani Basu (Yale)
K. Stassun (Vanderbilt)
J. Tayar (Hawai‘i)
M. Yıldız (İzmir)
Z. C. Orhan (İzmir)
S. Örtel (İzmir)
H. M. Antia (TIFR)
T. Appourchaux (Paris-Sud)
E. Corsaro (INAF)
G. Davies (Birmingham)
N. Themeßl (MPSS)
D. Huber (Hawai‘i)
Stellar helium abundances strongly determine their structure and evolution. However, since helium cannot be detected directly in the photospheres of most stars, helium abundances are one of the most poorly-constrained inputs to stellar models. It is therefore typical to assume a relationship with the initial abundances of other heavy elements, typically of linear form described by a gradient ΔY/ΔZ. No observational consensus exists regarding empirically reasonable values of ΔY/ΔZ, or, for that matter, even whether such a linear relation is observationally justifiable. Separately, asteroseismology has proven to be an excellent tool with which to study the structure of stars. In particular, asteroseismology permits the inference of stellar helium abundances, either directly through acoustic-glitch measurements, or indirectly through the forward modelling of stellar oscillation mode frequencies. Using constraints on the initial helium abundance derived from ensemble asteroseismology and stellar forward modelling against individual mode frequencies of a collection of field stars in the TESS, Kepler, and K2 fields, we characterise the helium-metallicity relation of the brightest stars in the solar neighbourhood.
schedule: Tuesday, 15:20 UT / 11:20 ET
Bálint Seli
(Konkoly Observatory)
Krisztián Vida (Konkoly Observatory),
Attila Moór (Konkoly Observatory),
András Pál (Konkoly Observatory),
Katalin Oláh (Konkoly Observatory)
We present an analysis of TRAPPIST-1 like ultracool dwarfs with TESS full-frame image photometry, in order to constrain their average magnetic activity properties. The sample includes stars close to TRAPPIST-1 on the Gaia color-magnitude diagram, up to 50 pc. 248 of these objects have been observed during the first two years of the TESS primary mission, we used their light curves to search for flares and rotational modulation. The ages of 88 stars were estimated using kinematic information, but there seems to be no strong correlation with rotational period. The composite flare frequency distribution shows a power-law index similar to TRAPPIST-1, and it is extended to higher energies. The results imply that while superflares can be expected every few decades, the flare rate of such stars is insufficient to fully destroy the possible ozone layer of orbiting planets.
schedule: Tuesday, 14:10 UT / 10:10 ET
Samuel Grunblatt
(American Museum of Natural History/Center for Computational Astrophysics)
Samuel Grunblatt (AMNH/CCA), Joel C. Zinn (AMNH), Adrian Price-Whelan (CCA), Ruth Angus (AMNH/CCA), Nicholas Saunders (Hawaii), Marc Hon (Hawaii), Amalie Stokholm (Aarhus), Earl P. Bellinger (Aarhus), Sarah Martell (UNSW), Benoit Mosser (LESIA Paris), Emily Cunningham (CCA), Jamie Tayar (Hawaii), Daniel Huber (Hawaii), Jakob Lysgaard Rorsted (Aarhus), Victor Silva Aguirre (Aarhus)
The vast majority of Milky Way stellar halo stars were likely accreted from a small number of relatively large accretion events. However, the timing of these events is poorly constrained, relying on indirect dynamical mixing arguments or imprecise age measurements of stars associated with debris structures. Here, we aim to infer robust stellar ages for stars associated with galactic substructures to more directly constrain the merger history of the Galaxy. By combining kinematic and spectroscopic data with asteroseismology of TESS light curves, we infer stellar ages for a sample of 10 red giant stars that were kinematically selected to be associated with the stellar halo, a subset of which are associated with the Gaia-Enceladus halo substructure, and compare their ages to 3 red giant stars in the Galactic disk. We determine hierarchical ages for the populations of Gaia-Enceladus, halo and disk stars, finding a Gaia-Enceladus population age of 8 +/- 3 Gyr. This framework should allow distinct characterization of Galactic substructures using larger stellar samples and additional TESS data available in the near future.
schedule: Friday, 21:05 UT / 17:05 ET
Theron Carmichael
(Harvard University)
David Latham (Center for Astrophysics), Jonathan Irwin (Center for Astrophysics), George Zhou (Center for Astrophysics), Karen Collins (Center for Astrophysics), and the TESS Follow-up Observing Program Working Group
This talk presents an analysis of transiting brown dwarf (BD) systems and examines their effectiveness as tests to substellar evolutionary models. The radius, mass, and age of transiting BD systems are the parameters most useful in testing these models and in this work, I show how my collaborators and I have used the TESS mission, the TRES spectrograph (and other spectroscopic follow up), and the Gaia mission in tandem to detect and characterize 14 new transiting BD systems with precise radius, mass, and age determinations (in most cases). One system has an age estimate from gyrochronology, which we use to constrain the youth of one transiting BD, TOI-811b, to less than 200 Myr. In addition, I apply parallax measurements from Gaia DR2 to improve the radius determinations of 10 transiting BD systems published prior to Gaia DR2 and the launch of the TESS mission. This work has significantly improved the radius determinations of 7 previously known transiting BDs, including CoRoT-15b and AD 3116b, whose radius uncertainties have been improved from 15% to 5-7%, making them much more effective for testing substellar evolutionary models.
schedule: Tuesday, 14:35 UT / 10:35 ET
James A. G. Jackman
(Arizona State University)
Evgenya Shkolnik (ASU), Chase Million (Million Concepts), Scott Fleming (STScI)
Stellar flares are explosive phenomena that release radiation across the entire electromagnetic spectrum. The far-UV emission from flares can dissociate atmospheric species and exacerbate atmospheric erosion. Yet, the near-UV flux may be necessary for the emergence of life on rocky planets around low-mass stars such as TRAPPIST-1. A detailed knowledge of the UV energies and rates of flares is therefore essential for our understanding of the habitability of M dwarf systems. However, measurements of UV flare rates require expensive campaigns with HST, meaning habitability studies instead often use UV rates based on extrapolations from white-light studies with TESS. Despite their use in contemporary habitability studies, such extrapolations are untested and their accuracy remains unconstrained. To this end, we have combined TESS white-light and archival GALEX UV photometry for M dwarfs from TESS cycles 1 to 3 to test the UV predictions of habitability studies. We will show how white-light flare studies underestimate the UV rates of flares, how to correct for this effect, and the impact our results have on our current understanding of the UV environments of exoplanets around M dwarfs.
schedule: Friday, 21:20 UT / 17:20 ET
Mark Popinchalk
(CUNY/AMNH)
Jacqueline Faherty (AMNH), Jason Curtis (Columbia), Daniella Bardalez-Gagliuffi (AMNH), Johanna Vos (AMNH), Lisseth Gonzales (AMNH), Andrew Ayala (AMNH)
The local volume around the Sun is a laboratory for studying all aspects of star and planet formation. This is especially true regarding co-moving, co-evolving young associations. Since the release of Gaia DR2 and now Gaia eDR3, there have been a multitude of papers examining new coherent structures of stars near the Sun which allow us to establish precise ages. TESS has enabled us to inspect these ages using gyrochronology while concurrently reinvestigating the membership of certain objects with kinematics supplemented by rotation rates. We have measured rotation periods for hundreds of objects across 26 different associations with ages ranging from 10 Myr to 700 Myr. We used TESS FFI light curves as they yield reasonable rotation rates even when extracted from the raw data. We used a carefully vetted list of bonafide, candidate and potential members of new and known associations using full kinematics, Bayesian probability and radial velocities where possible. In this talk we will present our preliminary results of the color-period plots for several associations that demonstrate intriguing structure across mass and age which is likely linked to the physical evolution of stars across the main sequence.
schedule: Friday, 20:25 UT / 16:25 ET
Matteo Cantiello
(CCA & Princeton)
Matteo Cantiello (CCA & Princeton), Daniel Lecoanet (Northwestern), Adam S. Jermyn (CCA), Luca Grassitelli (Bonn)
TESS observations have revealed a new type of variability: stochastic low-frequency photometric variability (SLF). This type of variability is ubiquitous in early type stars. It has been suggested that SLF arises due to either subsurface convection or internal gravity waves launched by the convective core. Here we show that relevant properties of convection in subsurface convective layers correlate very well with the timescale and amplitude of stochastic low-frequency photometric variability, as well as with the amplitude of macroturbulence. We suggest that SLF and surface turbulence in massive stars are caused by the the presence of subsurface convection. We show that an explanation for the observed surface photometric variability and macroturbulence relying on convective core driven internal gravity waves encounters a number of difficulties, and seems unlikely to be able to explain the observed trends.
schedule: Tuesday, 14:50 UT / 10:50 ET
Elsa Katarina Palumbo
(Caltech)
Benjamin T. Montet (University of New South Wales), Adina D. Feinstein (University of Chicago), Luke Bouma (Princeton University), Joel Hartman (Princeton University), Lynne Hillenbrand (California Institute of Technology), Michael Gully-Santiago (University of Texas at Austin)
Magnetospheric clouds, plasma that accumulates in dense clumps at a star's corrotation radius, have been proposed as an explanation for variable dips in the light curves of young stars such as σ Ori E and RIK-210. However, the stellar theory that first predicted magnetospheric clouds also anticipated centrifugal breakout, an associated mass-loss mechanism for which there has been limited empirical evidence. Based on data from TESS, Gaia, LCO, ASAS-SN, and Veloce, we propose that the 45-million-year-old M 3.5 star TIC 234284556 is a candidate for a direct detection of centrifugal breakout. To assess this hypothesis, we examine changes in the dip parameters over three sectors of TESS data, analyze optical flaring as a proxy for magnetic activity, and interpret the presence of an anomalous brightening event that precedes the disappearance of the dip. We argue that TIC 234284556 and previously identified ``flux-dip" stars together give us compelling evidence that centrifugal breakout is an important mass-loss mechanism. Finally, we consider possible mass-accumulation mechanisms and discuss how future observations may help us constrain M dwarfs’ wind mass loss rates or give us valuable data about extra-solar CMEs.
schedule: Tuesday, 13:55 UT / 09:55 ET
Krzysztof Hełminiak
(NCAC Toruń)
Since 2011 we have been conducting an extensive spectroscopic survey (CREME) of detached eclipsing binaries (DEBs), and obtaining precise radial velocity (RV) data for hundreds of DEBs. The main goal was to identify and properly characterize new cases of poorly-studied or astrophysically interesting stars (e.g. low mass dwarfs, PMS, giants, pulsators, multiples, etc...). For most of them (currently ~200) we also gathered 2-minute cadence time series photometry from TESS through GI programs. Thanks to the superb data sets we are able to derive the values of fundamental stellar parameters (e.g. absolute masses, radii, temperatures) with a very high relative precision of 0.2-2%. To date we have identified for example ~40 DEBs with low-mass stars, 15 with (sub)giants, ~10 with pulsators of various kinds, ~80 multiples, or 5 with PMS components, as well as a number of exoplanet and BD candidates associated with eclipsing binaries.
schedule: Wednesday, 21:45 UT / 17:45 ET
Travis Metcalfe
(White Dwarf Research Corp.)
Jennifer van Saders (U.Hawaii)
TESS Asteroseismic Science Consortium (TASC)
During the first half of main-sequence lifetimes, the evolution of rotation and magnetic activity in solar-type stars appears to be strongly coupled. Recent observations suggest that rotation rates evolve much more slowly beyond middle-age, while stellar activity continues to decline. One hypothesis to explain this decoupling is a shift in magnetic morphology from predominantly larger to smaller spatial scales. This hypothesis was recently tested with LBT spectropolarimetric measurements of the exoplanet host star rho CrB. We combine these observations with TESS asteroseismology to place new constraints on the evolution of magnetic morphology beyond middle-age. We then attempt to match these constraints with rotational evolution models, assuming either standard spin-down or weakened magnetic braking. We conclude that the asteroseismic age of rho CrB is consistent with the expected evolution of its mean activity level, and that weakened braking models can more readily explain its relatively fast rotation rate.
schedule: Wednesday, 21:30 UT / 17:30 ET
Tansu
(Massachusetts Institute of Technology)
A large number of non-interacting black holes are expected to exist close to the solar system that have so far evaded detection in X-rays. Black holes with stellar companions aligned edge-on yield light curves with a rich set of features including periodic brightening induced by microlensing in addition to phase modulations due to relativistic effects and tidal distortions. The former self-lensing signature is a unique and compelling evidence of compactness and can yield a precise (percent level) mass measurement for the lensing black hole with broad implications for probing the black hole mass gap. I present the results of a comprehensive search for close-in, detached black holes using the TESS primary mission data. Using injection-recovery tests, I discuss the selection function of the search pipeline by characterizing its recall and precision. Resulting constraints on the occurrence rate start probing the common-envelope formation mechanism of black holes with stellar companions. A future confirmed detection will likely yield the black hole closest to the solar system, acting as a prototype for subsequent population studies that will complement gravitational waves and Gaia astrometry as probes of the black hole mass function.
schedule: Tuesday, 15:05 UT / 11:05 ET
Kosuke Namekata
(National Astronomical Observatory of Japan)
Kosuke Namekata (1,2), Hiroyuki Maehara (2), Satoshi Honda (3), Yuta Notsu (4,5,6), Soshi Okamoto (1), Jun Takahashi (3), Masaki Takayama (3), Tomohito Ohshima (3), Tomoki Saito (3), Noriyuki Katoh (3), Miyako Tozuka (3), Katsuhiro L. Murata (6), Futa Ogawa (6), Masafumi Niwano (6), Ryo Adachi (6), Motoki Oeda (6), Kazuki Shiraishi (6), Keisuke Isogai (1), Daikichi Seki (1), Takako T. Ishii (1), Kiyoshi Ichimoto (1), Daisaku Nogami (1), Kazunari Shibata (1)
(1)Kyoto University, (2)NAOJ, (3) University of Hyogo, (4) University of Colorado Boulder, (5) National Solar Observatory, (6) Tokyo Institute of Technology
Solar flares are often accompanied by filament/prominence eruptions, sometimes leading to coronal mass ejections (CMEs) that directly affect the Earth's environment. `Superflares' are found on some active solar-type stars, but the association of filament eruptions/CMEs is unknown. We report the first optical spectroscopic observation of superflares on solar-type star EK Dra with the Seimei telescope. The existence of H$¥alpha$ emission was confirmed by the simultaneous TESS white-light superflare. The observation shows the first evidence for a stellar filament eruption associated with a superflare on the solar-type star. After the superflare brightenings with the radiated energy of 2.0×10^{33} erg observed by TESS, a blue-shifted H-alpha absorption component with a velocity of -510 km s^{-1} appeared. The velocity gradually decayed in 2 hour with the surface gravity on EK Dra. We found that the temporal changes in the spectra of EK Dra greatly resemble that of the-Sun-as-a-star solar filament eruption. Moreover, the stellar filament mass of $1.1¥times10^{18}$ g is 10 times larger than that of the largest solar CMEs. The filament eruption and a possible CME can greatly affect the planetary environment and stellar mass evolution.
schedule: Friday, 21:35 UT / 17:35 ET
Amber Medina
(Harvard-Smithsonian Center for Astrophysics)
Jennifer Winters (Harvard-Smithsonian Center for Astrophysics)
Jonathan Irwin (Harvard-Smithsonian Center for Astrophysics)
David Charbonneau (Harvard-Smithsonian Center for Astrophysics)
We present a study of the galactic kinematics, flare rates, chromospheric magnetic activity and rotation periods for an all-sky sample of 219 single stars within 15 parsecs and with masses between 0.1−0.3 M⊙ observed during the TESS primary mission. From multi-epoch high-resolution spectroscopy, we measure the equivalent widths of various activity indicators, and we determine the stellar radial velocity which, when combined with Gaia astrometry, permits us to determine the galactic UVW space motions. The fraction of active stars increases with decreasing stellar mass from 26% at 0.25 M⊙ to 44% at 0.17 M⊙. We find that stars with saturated flare rates have Rossby numbers less than 0.5 and belong to a kinetically cold population with ages less than 2 Gyr. The remaining stars have extremely low flare rates, long rotation periods, and kinematic ages in excess of 6 Gyr. We estimate the age at which stars transition from the rapidly flaring regime to the inactive one. This constraint on the history of the stellar radiation environment for the terrestrial planets known to orbit these stars will be important for interpreting planned JWST observations of their atmospheres.
schedule: Thursday, 19:45 UT / 15:45 ET
Tim White
(University of Sydney)
Benjamin Pope (University of Queensland)
TESS is providing a wonderful opportunity to observe the brightest stars in the sky, stars that often have a long and rich history of observation. However the brightness of such stars present unique challenges, with saturation of the TESS cameras leading to long bleed columns that may bleed off the edge of the CCD. Not only does this result in aperture losses when doing simple aperture photometry, but it can also cause over-subtracted smear corrections because of an excess of charge in the smear rows. This affects not only these bright stars, but any star along the same CCD column. I will present our tools for overcoming these issues, and introduce our new open-source software package, mundey, which recalibrates TESS target pixel files and fixes anomalous smear corrections. I will demonstrate the efficacy of these tools by presenting TESS light curves of some of the brightest and well-known stars in the sky, including Sirius, Procyon, Canopus, and Polaris.
schedule: Thursday, 14:05 UT / 10:05 ET
Belinda Nicholson
(University of Oxford)
Suzanne Aigrain (University of Oxford)
Quasi-periodic (QP) Gaussian Process (GP) models are increasingly popular to model stellar activity signals in light curves and radial velocity (RV) time-series, owing to their ease of use and flexibility. In this study we simulations of rotating stars with evolving star-spots to investigate the extent to which the hyper-parameters of the most popular QP GP kernel are related to the physical parameters of the spots, in particular rotation period and spot life-time. We also compare GP hyper-parameters obtained by fitting a) simulated space-based light curves (from e.g. Kepler, TESS or PLATO), RV time-series with regular sampling, and RV time-series with more realistic, ground-based time-sampling. Insights from this exercise can help in the planning and analysis of RV follow-up of transiting planets discovered by TESS.
schedule: Thursday, 19:30 UT / 15:30 ET
Michael Higgins
(Duke University)
Keaton Bell - NSF Astronomy and Astrophysics Postdoctoral Fellow, University of Washington
With a plate scale of 21"/pixel, essentially every TESS light curve is a blend of multiple, potentially variable stars. Blended light from nearby stars introduce complications in the analysis of TESS photometry. These complications can be difficult to identify by inspection, and can lead to the potential misattribution of variability to the wrong source. Here we present an open source software tool that streamlines the process of disentangling blended variable stars in TESS photometry. Given a list of measured frequencies of sinusoidal variability, we fit the location in the time series pixel data where the signal-to-noise ratio is distributed as the TESS's pixel response function. This process outputs a sky location of the signals with uncertainties, along with the relative probabilities of these signals originating from Gaia sources within the Target Pixel File.
schedule: Monday, 20:10 UT / 16:10 ET
Jason T. Hinkle
(University of Hawaii)
Benjamin J. Shappee (University of Hawaii), Patrick J. Vallely (Ohio State University), Michael M. Fasnaugh (MIT), Thomas W. -S Holoien (Carnegie Observatories), Katie Auchettl (University of Melbourne), Krzysztof Z. Stanek (Ohio State University), and Christopher S. Kochanek (Ohio State University)
The growth of ground-based transient surveys has driven the discovery of an increasing number of ambiguous nuclear transients (ANTs). Properties of such sources impede their identification as members of a known class, like tidal disruption events (when a star gets ripped apart by a black hole), AGN (actively accreting supermassive black holes), or supernovae. Thus, ANTs represent a unique opportunity to probe the full range of behaviors occurring in galactic centers. In particular, the fast cadence and high photometric precision of the Transiting Exoplanet Survey Satellite (TESS) allows for detailed studies of the variability properties of ANTs. Here, I discuss two ANTs discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN), each with multiple sectors of TESS data. The first, ASASSN-18el has been interpreted as a changing-look AGN, although the associated physical mechanism is unclear. The second, ASASSN-20hx paradoxically represents one of the most obvious ANTs to date. Using TESS data, I will provide constraints on pre-existing nuclear activity and measure flare rise/decline slopes. Finally, I will place these events in the context of known nuclear transient phenomena to establish a sample of well-studied ANTs.
schedule: Monday, 20:25 UT / 16:25 ET
Anna Payne
(Institute for Astronomy, University of Hawaii)
Benjamin Shappee (Institute for Astronomy, University of Hawaii), Katie Auchettl (University of Melbourne), Padi Boyd (NASA Goddard Space Flight Center), Michael Fausnaugh (Massachusetts Institute of Technology), Jason Hinkle (Institute for Astronomy, University of Hawaii), Thomas Holoien (Carnegie Observatories), Mark Huber (Institute for Astronomy, University of Hawaii), Christopher Kochanek (The Ohio State University), Jack Neustadt (The Ohio State University), K.Z. Stanek (The Ohio State University), Todd Thompson (The Ohio State University), Michael Tucker (Institute for Astronomy, University of Hawaii), Patrick Vallely (The Ohio State University)
ASASSN-14ko is a periodically flaring transient at the center of the AGN ESO 253-G003 with a slowly decreasing period. ASASSN-14ko is incredibly unique compared to other nuclear transients: the flares recur frequently ~3 times per year over the last 7 years, with signatures present over X-ray, UV, and optical wavelengths. TESS observed this galaxy at exactly the right time to capture two separate flares during Sectors 4-6 and Sectors 31-33, providing the most detailed look of ASASSN-14ko's optical flare evolution. The TESS data were crucial for precisely constraining the outbursts' rise and decline and their model fits. Furthermore, TESS allowed for well-constrained timing of the two peaks which provided anchors on the timing model to accurately predict future flares. The photometric precision and high cadence of TESS allowed us to detect the differences between the two flares in the optical, revealing concretely for the first time that not all flares in the optical are precisely the same, as was previously thought. We considered several scenarios to explain ASASSN-14ko's periodic flares, but currently the most likely explanation is a repeating partial tidal disruption event -- the first detection of its kind.
schedule: Monday, 20:40 UT / 16:40 ET
Colin Burke
(University of Illinois at Urbana-Champaign)
Yue Shen (U Illinois)
Yu-Ching Chen (U Illinois)
Simone Scaringi (Texas Tech)
Claude-Andre Faucher-Giguere (Northwestern)
Xin Liu (U Illinois)
Qian Yang (U Illinois)
Stochastic variability in active galactic nuclei (AGN) hosting supermassive black holes is ubiquitous across wavelengths and timescales. Unlike X-ray variability studies, measurements of high-quality optical light curves and power spectra of AGN are just beginning. A key question is if AGN variability properties can be related to physical properties of the accretion disk. In this talk, I will show early results from TESS demonstrating detection of variability in the archetypal dwarf AGN NGC 4395. Using the high-quality TESS light curve and careful systematic detrending, we found its variability properties are almost exactly as expected given its very low black hole mass of ~10^5 solar masses. This demonstrates the power of TESS light curves in identifying low-mass AGN with optical variability, and the potential to unlock a new window to our understanding of accretion disks across the entire range of supermassive black hole masses.
schedule: Friday, 13:50 UT / 09:50 ET
Csaba Kiss
(Konkoly Observatory)
Andras Pal (Konkoly Observatory, Hungary), Róbert Szakáts (Konkoly Observatory, Hungary), Thomas Müller (Max-Planck-Institut für extraterrestrische Physik, Germany)
Despite that they are the brightest representatives of trans-Neptunian objects, many dwarf planets still miss a well-determined light curve and hence rotation period, in many cases due to the biases and aliases of ground-based observations. In this presentation we show results from the analysis of TESS light curves of the Kuiper belt dwarf planets Eris, Makemake and Orcus. These data are combined with thermal emission measurements to constrain the spin axis orientation and determine how the light curve can be caused by surface features. As all the three targets have a companion, the rotational information is also incorporated into a tidal evolution model that can be used to constrain the formation scenarios of the system, and, in some cases, give hints on the internal structure and material properties.
schedule: Friday, 14:05 UT / 10:05 ET
Malena Rice
(Yale University)
Dan Foreman-Mackey (Center for Computational Astrophysics), Gabriella Contardo (Center for Computational Astrophysics), Greg Laughlin (Yale University)
In recent years, the observed orbital geometry of extreme trans-Neptunian objects (TNOs) has provided intriguing evidence suggesting the existence of an as-yet undiscovered “Planet Nine.” However, the statistical robustness of this claim has been heavily contested due to the uneven sky coverage of surveys searching for TNOs. We will present the first results from a new survey utilizing TESS full-frame images to search for TNOs, with a magnitude limit V~22. This survey is designed to extract the locations and magnitudes of undiscovered outer solar system objects, including both Planet Nine and the population of extreme trans-Neptunian objects pertinent to the Planet Nine hypothesis, using a blind shift-stacking search along all plausible outer solar system orbits. Together with the extensive sky coverage of the TESS mission, this search will place stringent constraints upon the undiscovered TNO population, with potential survey extensions to additional solar system populations.
schedule: Thursday, 14:20 UT / 10:20 ET
Michaël Cretignier
(Astronomy Department of the University of Geneva)
Xavier Dumusque, Yinan Zhao (Astronomy Department of the University of Geneva)
When the m/s level radial-velocity (RV) precision wants to be reached to follow-up transiting candidates, it is mandatory to mitigate at best stellar, instrumental and atmospheric signals.
To do so, we developed a new code, YARARA, that analyses a time-series of high-resolution spectra for any given star, and model, using a combination of data-driven and physically-motivated approaches, the different flux contributions from i) the used spectrograph, ii) the tellurics, and iii) stellar activity. The RV derived from the cleaned HARPS spectra show generally a ~20% decrease in rms, which can be associated to a mitigation of the different perturbing signals. YARARA can be implemented for any high-resolution spectrograph data.
To go a step further in mitigating stellar activity, we can use the line-by-line RVs or spectra provided by YARARA and apply machine learning techniques such as PCA, ICA and others to separate a planetary signal from stellar activity, as the former affects all the spectral lines in the same way, which is not the case for the latter.
YARARA plus data-driven approaches to separate stellar from planetary signal can significantly improve the detection of small-mass exoplanets.
schedule: Tuesday, 19:30 UT / 15:30 ET (panel)
Johanna Teske
(Carnegie Earth and Planets Laboratory)
Now is an exciting, perhaps "revolutionary", time to be an exoplanet scientist. Kepler provided us with a powerful foundation in exoplanet statistics and occurrence rates, which helped motivate the all-sky TESS Mission that has provided thousands of new, closer-by transiting planet candidates primed for detailed characterization. Spitzer and HST provided tantalizing glimpses of (mostly larger) exoplanet atmospheres, allowing us to pose hypotheses about atmospheric origin, evolution, and composition that will be addressed by the upcoming JWST. Furthermore, we are also in the midst of seminal growth in the ground-based detection and characterization of exoplanets via the radial velocity (RV) technique, a felicitous circumstance considering this technique kicked off observational exoplanet science over 25 years ago. In this talk, I will review the current state of precision RV science, describing the most cutting-edge instruments and what they are finding, as well as challenges to further advancement. I will also highlight how TESS is contributing to PRV science, and the synergies between the data analyses and results that are furthering our understanding of exoplanet evolution and demographics. Whether you are already a PRV fan, looking to learn more about how PRV and TESS connect, or both, this talk is for you!
schedule: Friday, 14:30 UT / 10:30 ET (panel)
Heike Rauer
(Institute of Planetary Research, DLR)
PLATO (PLAnetary Transits and Oscillations of stars) is ESA’s M3 mission and designed to detect and characterize extrasolar planets by high-precision, long-term photometric and asteroseismic monitoring of a large number of stars. PLATO will detect small planets around bright stars, including terrestrial planets in the habitable zone of solar-like stars. Planets will be characterized for their radius, mass, and age with high accuracy. PLATO will provide us the first large-scale catalogue of well-characterized small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories. Thanks to accurate age estimates, PLATO will give us the ground to determine the various formation and evolution pathways that lead to planet and planetary system diversity. It will allow a comparative exoplanetology and to place our solar system planets in a broader context. PLATO is scheduled for a launch date end 2026. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements to detect transiting planets and derive their radii and ages. The satellite data are complemented by a ground-based observing program to derive the planetary masses. This talk will present an overview of the PLATO instrument and the mission profile, its science goals, and its expected performances.
schedule: Tuesday, 13:00 UT / 09:00 ET (invited overview)
May Gade Pedersen
(KITP, UCSB)
A hundred years ago it was thought impossible that we would ever be able to study the interior physics of stars using in-situ observations. Less than fifty years later the first oscillations in the Sun were discovered and the field of helioseismology, which later also evolved into asteroseismology, started to take off. Asteroseismology is the study and interpretation of stellar oscillations, which penetrate deep into the stellar interiors and therefore carry information about the conditions within the star. This allows us to not only derive fundamental stellar parameters useful for the study of exoplanets, but also test our stellar structure and evolution models which form the basis of many fields in astrophysics. The past twenty years in particular have revolutionized the field of asteroseismology since the advent of space telescopes designed to provide high-precision, high-cadence, and long time base light curves of stars. This talk will provide a brief introduction to how asteroseismology works, as well as an overview of new insights gleaned from TESS for various oscillating stars across the HR diagram.
schedule: Monday, 19:30 UT / 15:30 ET (invited overview)
Michael Fausnaugh
(MIT)
With its large field-of-view and continuous monitoring, TESS opens a new window on transient and extragalactic time domain studies. I will review results from these fields over the last three years that were uniquely enabled by TESS. In particular, TESS data probes the physical processes governing gamma-ray emission in classical novae, and is adding to our understanding of accretion processes in active galactic nuclei and tidal disruption events. TESS can also observe supernovae at the moment of explosion, which provides crucial data for supernova explosion physics and the nature of Type Ia supernova progenitors. I will conclude by describing likely contributions that TESS will make to transient and extragalactic astrophysics in the next year and future extended missions.
schedule: Friday, 19:30 UT / 15:30 ET (invited overview)
Jamie Tayar
(Institute for Astronomy, University of Hawaii)
There are still significant gaps in our understanding of stellar evolution, including questions related to rotation, magnetism, convection, and mixing. Kepler taught us many things, but it was limited in its fields, cadence, and sample size. I will show how the data from the TESS mission is allowing us to search for new types of variability, giving larger samples, providing additional information on old puzzles, and allowing us to combine photometry with the other types of data available for these bright stars. I will discuss how we can use this new data to better understand the physics of stellar interiors and evolution, and in turn use that understanding to make better models of stars, which can then be applied to characterizing exoplanetary systems as well as the populations of our own and other galaxies.
schedule: Wednesday, 13:54 UT / 09:54 ET (splinter talk)
Nicholas Saunders
(Institute for Astronomy, University of Hawai‘i)
While the population of confirmed exoplanets around main-sequence stars continues to grow, the sample of planets transiting evolved stars is still limited, and traditional planet-search pipelines are not optimized for these stars. To uncover more planets orbiting post-main-sequence hosts, we have created a TESS photometry and planet search pipeline designed to target evolved stars using Full-Frame Image data. We present the first results from our search, highlighting the discovery of four hot Jupiters orbiting stars ranging from the subgiant to the red-giant branch. Using TESS photometry, ground-based photometry, and radial velocity measurements, we report masses between 0.5 and 2.0 Jupiter masses and radii between and 0.9 and 1.9 Jupiter radii. Two planets have periods <3 days, less than half the previous shortest known period of any planet around a red giant star. Additionally, two of the planets appear to be highly inflated, while the other two do not show any sign of inflation. The large spread in radii implies a complex relationship between planet mass, radius, incident flux, orbital properties and inflation efficiency. Our continued search will produce a statistical sample of planets which can be used to test theories of planet inflation and migration, and probe the demographics of planetary system evolution.
schedule: Friday, 14:30 UT / 10:30 ET (panel)
Willy Benz
(University of Bern)
The CHaracterising ExOPlanet Satellite (CHEOPS) was selected in 2012 as the first small mission (S-mission) in the ESA Science Programme and successfully launched on December 18, 2020 on a Soyouz-Fregat rocket from Kourou, French Guyana. It is a joint mission of ESA and Switzerland with important contribution by 10 additional ESA Member States. CHEOPS is the first mission dedicated to search for transits of exoplanets by means of ultrahigh precision photometry on bright stars already known to host planets. As a follow-up mission, CHEOPS is mainly dedicated to improving whenever possible existing radii measurements or provide first accurate measurements for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. By unveiling transiting exoplanets with high potential for in-depth characterization, CHEOPS will also provide prime targets for future instruments suited to the spectroscopic characterisation of exoplanetary atmospheres. A nominal mission duration of 3.5 years is foreseen to enable the execution of a broad and diverse science programme.
schedule: Tuesday, 19:30 UT / 15:30 ET (panel)
Juliette C Becker
(Caltech)
To make the connection between the current states of exoplanet systems and their dynamical histories (including how planets may have formed and migrated), it is important that an orbital solution provides not just measures of the radii and masses of planets, but also the planetary orbital eccentricities and relative angular alignments. With sufficient quantity and quality of transit data, these important parameters can be extracted using transit timing variations (TTVs), presenting unique insights to the architectures of particularly multi-planet system. In this talk, I will summarize the recent history of TTVs and how TESS TTV data can be used to improve orbital solutions, discover unseen planets, and constrain planetary masses.
schedule: Wednesday, 19:30 UT / 15:30 ET (panel)
Ruth Angus
(American Museum of Natural History & Flatiron Institute)
TESS provides many new opportunities to study young stars and exoplanets. For example, its light curves could help identify stars in young moving groups via their rotation periods, could reveal new young extrasolar planets, and could provide data needed to calibrate age-rotation relations for young stars and M dwarfs. In this talk I will discuss different methods available for dating cool young stars. TESS is particularly sensitive to the rotational variability of relatively rapidly rotating stars which are often young. I will discuss the promise and challenges presented by rotation-dating, also known as gyrochronology, for these rapidly rotating, young stars.
schedule: Thursday, 20:20 UT / 16:20 ET (splinter talk)
Eliza Kempton
(University of Maryland)
The Atmospheric Characterization Working Group (ACWG) for NASA's TESS mission was initially envisioned to conduct pre-launch activities for maximizing TESS's impact on exoplanet atmosphere studies. Now that TESS has completed its prime mission and entered its extended mission phase, the ACWG has shifted its focus. Currently and going forward, the role of the ACWG is to ensure the successful legacy of the TESS mission, specifically as it relates to the atmospheric characterization of its discovered exoplanets. In this context, success means pursuing a goal that the TESS-discovered exoplanets be observed by an optimal set of ground-based and spaced-based facilities in a coordinated manner, so as to extract population-level and individual planets' atmospheric properties. In this talk I will introduce the activities that the TESS ACWG has been undertaking to support its main goals. I will review criteria for joining the ACWG, and I will present the many ways in which the ACWG is working to support the atmospheric characterization community as it endeavors to further our understanding of the multitude of TESS-discovered exoplanets.
schedule: Thursday, 21:00 UT / 17:00 ET (splinter talk)
Néstor Espinoza
(Space Telescope Science Institute)
The technique of transmission spectroscopy -the variation of the planetary radius with wavelength due to opacity sources in the planet’s terminator region- has been to date one of the most successful in the characterization of exoplanet atmospheres, providing key insights into the composition and structure of these distant worlds. One underlying assumption of the technique, however, is that the variations are the same in the entire terminator region. In reality, the morning and evening terminators might have distinct temperature, pressure and thus compositional profiles due to the inherent 3D nature of the planet which would, in turn, give rise to different spectra on each side of it. Motivated by the fascinating prospects of detecting this effect, we have started a theoretical and observational effort aimed at constraining these morning-to-evening signatures using the most precise transit lightcurves obtained by TESS to date. In this contribution, we present the first results of this effort, which includes a complete analysis of all known transiting exoplanets observed by TESS to date, a thorough study of lightcurve detrending methods and the most precise constraints on the morning and evening limbs on a distant exoplanet.
schedule: Thursday, 20:30 UT / 16:30 ET (splinter talk)
Kevin Heng
(University of Bern)
The study of the albedos of Solar System objects is at least a century old, at least in the Western world. The light of a planet or moon varying with orbital phase is known as its phase curve. I will concisely review and discuss historically important work, including seminal contributions by Lommel (1887), Seeliger (1888), Chandrasekhar (1960), Sobolev (1975) and Hapke (1981). These introductions set the stage for a detailed discussion of our recent work on generalising these classic works to derive closed-form, ab initio solutions for the geometric albedo and reflected light phase curve. This novel theoretical framework is applied to Kepler space telescope data of the hot Jupiter Kepler-7b, where we demonstrate that one may infer fundamental aerosol (single-scattering albedo, scattering asymmetry factor) and atmospheric (geometric albedo, Bond albedo, phase integral) properties from precise photometry alone, thus providing powerful complementary information to spectra. Another case study are the Cassini phase curves of Jupiter. By inverting the Cassini phase curves, we infer that aerosols in the Jovian atmosphere are large, irregular, polydisperse particles that may be responsible for causing coherent backscattering of sunlight.
schedule: Thursday, 20:50 UT / 16:50 ET (splinter talk)
Daniel Apai
(The University of Arizona)
The interplay between condensate clouds and atmospheric circulation is a key component in giant exoplanet atmosphere models, but one that is very difficult to observationally constrain. Brown dwarfs are easier-to-observe proxies of weakly-irradiated giant planets, which make up the majority of the giant exoplanet population. Brown dwarfs display rotational modulations, possibly due to their cloud cover modulated by planetary-scale waves. However, the long-term, continuous, high-precision monitoring data to test this hypothesis is lacking. We present here a high-precision lightcurve of the closest brown dwarfs, the binary system Luhman 16 AB. The TESS data, which cover about 100 rotations of Luhman 16 B, display continuous lightcurve evolution. The periodogram analysis reveals unprecedented information on atmospheric dynamics, rotation, and system geometry. Among other results, we find clear evidence for multiple high-speed atmospheric jets and zonal circulation in Luhman 16B. Our study provides what is likely the most constraining dataset on atmospheric circulation on weakly-irradiated brown dwarfs and giant exoplanets and paves the way toward direct observational tests of general circulation model predictions.
schedule: Thursday, 21:10 UT / 17:10 ET (splinter talk)
Dimitra Atri
(NYU Abu Dhabi)
Stellar XUV radiation and energetic charged particles impact planetary atmospheres by inducing atmospheric escape, changes in chemistry and enhancing biological radiation dose on the surface. These effects can significantly impact planetary habitability. We use the Flare Frequency Distribution (FFD) of stars observed by Transiting Exoplanet Survey Satellite (TESS) to calculate atmospheric escape rates of potentially habitable planets through the hydrodynamic escape channel. We compare the integrated loss of planetary atmospheres from flares and steady state stellar XUV around FGKM stars over 5 billion years and discuss its impact on their potential habitability. We also model how stellar particle events interact with exoplanetary magnetospheres and enhance radiation dose on their surfaces. Finally, we discuss studying these phenomena in greater detail on Mars using MAVEN data.
schedule: Wednesday, 14:18 UT / 10:18 ET (splinter talk)
Alex Hindle
(Newcastle University)
Recent westward hotspot/brightspot offset measurements present significant exceptions from the norm of eastward hotspots found in the general hot Jupiter population. If these signals are to be trusted, they cannot be explained by hydrodynamic theory of synchronously rotating hot Jupiters, which predicts hotspots are always recirculated eastward of the substellar point. However, 3D magnetohydrodynamic (MHD) simulations predicted westward hotspot offsets would be possible in the hottest hot Jupiters (ultra-hot Jupiters). This is consistent with the emerging observational evidence as four out of the five westward measurements have been made on ultra-hot Jupiters, including one using TESS. Until now, however, the MHD mechanism that can drive such reversals has not been well understood. This talk will cover the findings of two recently submitted papers regarding the magnetic reversal mechanism. In the first part we will identify MHD mechanism responsible for hotspot reversals. In the second part, will physical consequences of the mechanism and apply a physically-motivated reversal criterion to a hot Jupiter dataset. Consequences include observational constraints of magnetic fields strengths and testable predictions that TESS can probe.
schedule: Thursday, 21:20 UT / 17:20 ET (splinter talk)
Alex Hindle
(Newcastle University)
Recent westward hotspot/brightspot offset measurements present significant exceptions from the norm of eastward hotspots found in the general hot Jupiter population. If these signals are to be trusted, they cannot be explained by hydrodynamic theory of synchronously rotating hot Jupiters, which predicts hotspots are always recirculated eastward of the substellar point. However, 3D magnetohydrodynamic (MHD) simulations predicted westward hotspot offsets would be possible in the hottest hot Jupiters (ultra-hot Jupiters). This is consistent with the emerging observational evidence as four out of the five westward measurements have been made on ultra-hot Jupiters, including one using TESS. Until now, however, the MHD mechanism that can drive such reversals has not been well understood. This talk will cover the findings of two recently submitted papers regarding the magnetic reversal mechanism. In the first part we will identify MHD mechanism responsible for hotspot reversals. In the second part, will physical consequences of the mechanism and apply a physically-motivated reversal criterion to a hot Jupiter dataset. Consequences include observational constraints of magnetic fields strengths and testable predictions that TESS can probe.
schedule: Thursday, 20:40 UT / 16:40 ET (splinter talk)
Johanna Teske
(Carnegie Earth and Planets Laboratory)
A comprehensive and accurate understanding of planet formation requires robust population studies, which incorporate characterizations of individual systems as part of a larger analysis designed to reveal trends between planet properties. By applying the capabilities of JWST to the new, bright targets from TESS, population studies of small exoplanet atmospheres will be possible for the first time; currently only a handful of planets smaller than Neptune have atmospheric measurements. In such population-level studies it is important to consider the decisions and biases built into ensemble observations. In this talk, we will discuss lessons learned from a simulated survey of 12 TESS planet atmospheres using JWST’s NIRSpec G395H. Specifically, we investigate the impact that sample selection has on the recovery of an injected relationship between small (1-3 Re) planet radii and their atmospheric molecular ratios, which represent key diagnostics of atmospheric processes such as outgassing, disk accretion, and atmospheric escape. Our results can guide future allocation of telescope time that is meant to reveal underlying trends in exoplanet atmosphere properties and, by extension, formation/evolution processes.
schedule: Wednesday, 19:30 UT / 15:30 ET (panel)
George Zhou
(University of Southern Queensland)
Close-in Super-Earths and Neptunes occupy 30-50% of Sun-like stars, yet we have no analog in our own Solar System. How did these planets form and evolve, and why does our Solar System differ from those we are finding elsewhere? Studying planets around young stars is the next best thing to growing planets in laboratories. TESS is finding dozens of planets around bright young stars in nearby clusters, associations, and in the field. For the first time, these planets are found transiting stars bright enough for a wide variety of follow-up observations. Already, the transit shadows of half a dozen of these planets have been detected in spectroscopic observations, mapping the projected orbital obliquities of a series of Neptune sized planets between the ages of 10 to 500 Myr. Transmission spectroscopic signatures have been searched for for these same planets, with most focusing on detecting signatures of ongoing atmospheric evaporation that may reveal the mechanisms behind early mass loss in Neptune-sized close-in planets. As we better understand the drivers behind the radial velocity jitter of young active stars, and as more infrared high resolution spectrographs come online, we are looking forward to mass measurements and constraints for many of these planets. Together, the planets being discovered by TESS will help write a tale of formation, migration, and evaporation for Neptune sized planets within the first 500 Myr of their lifetimes.
schedule: Thursday, 13:00 UT / 09:00 ET (panel)
Jason Eastman
(Center for Astrophysics | Harvard & Smithsonian)
Radial Velocities allow us to measure a planet's mass, and transit light curves allow us to measure the planet's radius. However, doing so requires we know the same parameters for the planet's host star. In addition, the transit duration, planetary eccentricity, and stellar density are inextricably linked, and detailed corrections like the light travel time delay require knowledge of the stellar parameters during the fit and are important effects that are observable in many systems today. The interdependence of these models means that a simultaneous, global model is greater than the sum of its parts. I will discuss the benefits and mechanics of performing such global fits, with special focus on properly accounting for systematic errors in the stellar atmospheric and evolutionary models, which have dominated the uncertainties for most exoplanet host stars since the release of Gaia DR2.
schedule: Thursday, 13:00 UT / 09:00 ET (panel)
Adina Feinstein
(University of Chicago)
TESS is performing a time-series photometry survey covering over 80% of the sky, providing an unprecedented quantity of data during the mission lifetime. While many stars are observed at 2-minute cadence, tens of millions of objects, including stars, extragalactic sources, and solar system bodies, are only observed with the TESS Full-Frame Images (FFIs). Many teams in the community have developed tools and provided publicly available light curves from the FFIs to enable a broad range of science. Here, I will give a general overview of the methods used to extract light curves from the FFIs. I will discuss the science goals from each team that has produced publicly available light curves to help guide users towards the best light curve for their science. I will provide quick demonstrations for how to retrieve these light curves and highlight software tools that allow for user-customized light curve extraction to better enable individual science goals.
schedule: Tuesday, 19:30 UT / 15:30 ET (panel)
Daniel Thorngren
(iREx, University of Montreal)
The study of exoplanet interiors allows us to infer their bulk compositions and evolution history, connecting their present-day state to their formation conditions. Such models generally require a well-measured mass, radius, and orbital information. TESS and the associated follow-up radial velocity programs are well-situated to collect this data for a very large number of new discoveries, dramatically expanding the dataset we have to work with. In this talk, I will review how interior structure models work and our resulting present understanding of exoplanet interiors, especially their composition and hot Jupiter radius anomalies. I will then highlight areas where the expanded planet sample from TESS will be particularly useful.
schedule: Thursday, 20:00 UT / 16:00 ET (splinter session)
Tansu Daylan
(Massachusetts Institute of Technology)
TESS continues to find planet candidates suitable for mass measurement, and hence, atmospheric characterization (AC). As the survey matures, the population and diversity of this exoplanet population grows and preliminary results on the AC of TESS-confirmed planets are emerging. This splinter session on the AC will be focused on TESS exoplanet discoveries that are suitable or even prime targets for AC as well as recent on AC results on exoplanets discovered by TESS.
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter session)
Brian Jackson
(Boise State University)
Perched on the precipice of disruption, ultra-hot Jupiters pose challenges to theories of planet formation and evolution. Yet, due to observational biases, they often dominate constraints on atmospheric composition, meteorology, and more. Furthermore, their hot temperatures allow TESS to directly characterize their atmospheric dynamics through thermal phase curve measurement. Meanwhile, small planets in ultra-short-period orbits are hot enough to have lakes of molten lava on their daysides. Some have even been observed disintegrating. This splinter session will gather experts in the detection, characterization, and theory of ultra-hot Jupiters and small ultra-short-period planets and in the relation of the planets to their host stars. The session will explore approaches to discovery and follow-up tailored to the unique opportunities and challenges of the TESS mission.
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter session)
Hugh Osborn
(MIT)
CHEOPS is an ESA space telescope focused on the high-precision photometric follow-up of transiting planets, allowing close synergies with TESS and fulfilling a scientific goal of TFOP SG5. Now with 18 months of observations, it is producing science results pertinent to the TESS community that include several studies focused on the follow-up of TOIs. This splinter session will outline the utility of CHEOPS for TESS follow-up, as well as allow presentations and discussions of CHEOPS observations of TOIs and other interesting results from both guaranteed time (GTO) and guest observer (GO) observations.
schedule: Thursday, 20:00 UT / 16:00 ET (splinter session)
Samuel Grunblatt
(American Museum of Natural History)
The goal of this splinter session will be to discuss the different FFI light curve pipelines currently available, and better understand their similarities and differences. This will involve presentations discussing the photometric pipelines of the MIT QLP, eleanor, TASOC, and giants light curves, with presentations from architects of each of these pipelines over the first hour. In the second hour, a preselected subset of targets will be compared using all the different pipelines to see which pipeline is best in which scenario. This time will be more open-ended, and will encourage either interaction from the session participants to recommend use-cases or targets of interest, or hack time to help new users become acquainted with these light curves.
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter session)
Rebekah Hounsell
(University of Maryland, Baltimore County)
The NASA Transiting Exoplanet Survey Satellite (TESS) entered the second year of its extended mission in June of 2021. Given that the extended mission is guest investigator driven, the areas of science investigated have greatly expanded beyond that of exoplanets. A variety of new TESS data products are also available, be those produced by the mission or as higher level science products available via MAST. To assist the user community in analyzing these data, a new version of the Lightkurve package has been released. Lightkurve v2.0 now has several improved features allowing the user to more easily understand and manipulate the TESS data. In this splinter session we aim to teach the user how to access, analyze, and manipulate data from TESS. All tools presented will teach the user how to work with time series data for the purpose of scientific research. A set of Jupyter notebooks have been created via a collaboration between NumFocus, MAST, Lightkurve, and TESS GI office. The workshop assumes a basic knowledge of python and astronomy and will walk the user through several of the concepts outlined below, * What kinds of TESS data products exist and how to access them from the MAST archive * How to use Lightkurve to access the various data products and create a time series for several different types of astrophysical objects * How to analyze and assess various data anomalies and how you might visualize them to improve their removal * How to account for instrumental and noise effects within your data
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter session)
David Armstrong
(University of Warwick)
Astrophysical uses for machine learning (ML) techniques are growing at pace, with regular developments in exoplanet vetting and validation and a growing body of work utilising ML algorithms to hunt for objects of special scientific interest in large-scale surveys. TESS is no exception, with recent work searching for eclipsing binaries, variable stars, dippers and more. In particular ML is now routinely used to identify false positives in transiting planet surveys, and sometimes to find the candidate transits themselves. State of the art algorithms are even capable of performing full planet validation at speed, opening the door to exciting new statistical possibilities. We propose a splinter focused on machine learning applied to the TESS dataset, for the community to share and compare techniques, establishing the state of the art and building a network of researchers interested in the field. This splinter will bridge the exoplanet and variable star communities and be an opportunity for young researchers from all areas impacted by TESS to present their work.
schedule: Thursday, 20:00 UT / 16:00 ET (splinter session)
Louise D. Nielsen
(Oxford University)
The TESS mission has discovered several exoplanets transiting young (age < 1 Gyr), bright stars, such as AU Mic, TOI-451 and DS Tuc A. These systems provide unique insights into the early stages of exoplanet evolution and how processes of atmospheric escape, dynamical interactions, and cooling over time shape planets and planetary system architectures. However, young systems are challenging to work with, mainly because of the highly active host stars. These make detections of young planets in transit light curves, as well as in-depth characterisation, very difficult. In this splinter session, we propose to discuss the challenges of detecting and characterising young TESS planets. This includes light curve extraction, identifying false positives, modelling stellar activity, paths towards robust planetary mass-measurements, atmospheric characterisation and determining spin-orbit alignment through the Rossiter–McLaughlin effect. The session will have close ties to the TESS-community investigating (young) stellar astrophysics, and refining knowledge of group/cluster/associations memberships based on GAIA DR3.
schedule: Wednesday, 14:30 UT / 10:30 ET (splinter session)
Ann Marie Cody
(SETI Institute)
Within the TESS full frame images are tens of millions of stars observed at 10 or 30-minute cadence. The light curves of these targets offer a unique opportunity to support searches for extraterrestrial intelligence (SETI). In this session, we will provide attendees with an overview of the synergistic research activities uniting the TESS mission and SETI efforts. We will discuss our ongoing search for technosignatures, as well as solicit presentations from astronomers involved in radio follow-up of TESS targets. The session will conclude with a group discussion on further possibilities to unite TESS and SETI.
schedule: Tuesday, 19:30 UT / 15:30 ET (panel)
Diana Valencia
(University of Toronto, Scarborough)
The first mass and radius measurements of a super-Earth, namely CoRoT-7b and followed closely with GJ1214b, HAPPENED in 2009 which marked THE first time we inferred the composition of two low-mass planet outside the solar system. It has taken more than a decade of expensive missions and time-consuming efforts to build a sample of low-mass exoplanets with both measured masses and radii that can tell us about the composition of distant small worlds. These initiatives include the launch of Kepler, TESS, and ground based CAMPAIGNS (Trappist and Mearth) to measure the radii of low-mass exoplanets, and numerous ground-based efforts to measure their masses. Finally, we have a sizeable sample that can reveal what compositions ARE REALIZED in exoplanets, and thus, constrain the possible formation pathways. In this talk, I will discuss what we have learned about the composition of super-Earths as a population, the present limitations in the sample and analysis, and propose ways to move forward.
schedule: Thursday, 20:40 UT / 16:40 ET (splinter talk)
Luke Bouma
(Princeton University)
I'll discuss two interrelated points that seem to be emerging from the fusion of Gaia, TESS, Kepler, and ground-based spectroscopy. First: some previously discovered planets have ages that can now be measured. Second: the halos of open clusters are often more populous than their cores, and require careful cleaning before they can be used for exoplanetary and stellar astrophysics. On the first point, I'll describe an adolescent mini-Neptune in the Kepler field (Kepler 1627 Ab; R=3.6 Re, P=7.2 days, t=35 Myr old; probably prograde). The planet's membership in the δ Lyr cluster was previously noted based on Gaia kinematics, and is confirmed using stellar rotation periods and photospheric lithium abundances. On the second point, I'll discuss the halo of a 150 Myr open cluster (NGC 2516), and a hot Jupiter that could reside in said halo (TOI 1937 Ab; M=1.8 Mjup, Porb=0.95 days, Pspin=6.5 days for a G2V host). From TESS rotation periods, we have found that the halo itself is elliptical and spans roughly 500 pc in the plane of the Galaxy (arXiv:2107.08050). However the star is lithium-poor, and the field star contamination rate in its vicinity is 50%; TOI 1937 Ab is either a young hot Jupiter, or it is tidally spun up.
schedule: Wednesday, 19:30 UT / 15:30 ET (panel)
Jason Curtis
(Columbia University)
Gaia has revealed that the solar neighborhood is teeming with stellar structures, some stretching hundreds of parsecs in space in elongated patterns, some arranged in more amorphous distributions, and some that are dense clusters with halos and tails. Are these structures composed of stars produced by the same star-forming episodes? The answer to this question will teach us about how stars form in structures and how the Galaxy evolves as they disperse and their stars join the field population. Identifying young stars, especially those still associated with their siblings, also lets us witness how the properties and behaviors of stars (e.g., sizes/luminosities, rotation and magnetic phenomena, elemental abundances) change over time. And those hosting planets are precious touchstones for understanding the physical mechanisms governing the early evolution of planetary sizes, atmospheres, and orbits. I will discuss how the various indicators of stellar youth are used to make sense of this new view of the solar neighborhood.
schedule: Friday, 13:00 UT / 09:00 ET (panel)
Deborah Woods
(MIT Lincoln Laboratory)
Our team has developed an image processing pipeline to discover asteroids in the TESS full frame images for the Lincoln Near-Earth Asteroid Research (LINEAR) program, which is sponsored by the NASA NEO Observations Program. The LINEAR-TESS pipeline is currently in operation and regularly reporting asteroid observations to the Minor Planet Center. To date we have submitted 19 million measured positions of approximately 55,000 unique solar system objects, including main belt asteroids, near-Earth asteroids, and comets. The data include hundreds of potential discoveries awaiting confirmation. In this talk I will discuss the algorithms and methodology utilized to push the limits of the astrometric accuracy and photometric sensitivity of the TESS instrument for asteroid detection without a priori information on the ephemerides of the objects. I will also discuss implications for asteroid interference in the measurement of stellar light curves and expectations for the frequency of these events in the upcoming ecliptic plane observations.
schedule: Wednesday, 19:30 UT / 15:30 ET (panel)
Ann Marie Cody
(SETI Institute)
The youngest stars-- those in the 1 to 5 million year (Myr) age range-- display high levels of variability over a large range of amplitudes and timescales. Flux variations are associated with infalling gas, circumstellar dust structure, and magnetic activity. As such, young stellar object (YSO) variability is intimately connected with the end stages of star formation and the beginnings of planet formation. Photometric monitoring campaigns on YSOs are currently one of the best ways to map out the circumstellar environment from the photosphere into the inner AU of the protoplanetary disk. While YSOs are observable from the ground, their light curves can be difficult to decipher because of gaps due to weather, sunlight, and instrument availability. Over the past decade, space telescopes have provided the first continuous photometric time series of young stars, at relatively high precision (<1%) and cadence (<1 hour). Data from CoRoT, MOST, Kepler, and now TESS, are enabling an unprecedented exploration of the connection between YSO variability and the physical conditions regulating star and planet formation. Prior to TESS, most of the objects surveyed were in the low-mass range, with temperatures comparable to that of the Sun and cooler. Light curve analysis revealed numerous distinct types of variability behavior, from periodic to stochastic, and fading to bursting. Now with TESS we have the chance to probe the brighter higher mass objects, including the Herbig Ae/Be stars. By comparing the variability behavior over a large range of stellar types, we are now gaining insight into how the circumstellar and planet-forming environments change as a function of mass. In addition, TESS's nearly all-sky coverage is uncovering groups of lower mass young stars by virtue of their variability alone.
schedule: Thursday, 13:00 UT / 09:00 ET (panel)
Rodrigo Luger
(Flatiron Institute)
In this pedagogical talk I will motivate linear models as an efficient and powerful tool for modeling systematics in TESS light curves. I will focus in particular on the distinction between "de-trending", in which systematics are corrected for or removed in a preprocessing step, and "marginalization", in which one models the physical quantities of interest while marginalizing (integrating) over the systematics. While the latter is less commonly used in the literature, it can often avoid problems with overfitting while ensuring uncertainties are correctly propagated to the final result. I will show several examples of how to build these linear models and how they have been applied in the literature. I will conclude with links to several resources for constructing and using them in your own work.
schedule: Wednesday, 14:30 UT / 10:30 ET (splinter talk)
Ann Marie Cody
(SETI Institute)
Through its set of full frame images, TESS is observing tens of millions of stars at 30-minute cadence. The resulting light curves are being used to study a variety of sources, from transiting exoplanet systems, to spotted stars, to pulsators. But with such a large dataset, there may also be new or unappreciated types of stellar variability. With TESS's predecessor, Kepler, astronomers and citizen scientists indeed identified a handful of stars undergoing unexplained fading events. The most well known of these-- Boyajian's star--ignited interest in stellar occultation phenomena. While most fading events are likely caused by the passage of dust in front of a star, alternative explanations lie with larger objects such as exocomets or even artificial structures put in place by intelligent civilizations. While this last possibility is unlikely, TESS presents us with a unique opportunity to conduct a search for such transiting megastructures. In contrast to Kepler, TESS will observe a much larger area of the sky, with orders of magnitude more targets. This enables a search for extraterrestrial life that is complementary to biosignature studies which probe for signs of more primative organisms and their precursors. The most likely result of such a technosignature search is an upper limit on the prevalence of technologically advanced life forms. We argue that this is still an important endeavor to undertake, as it will inform future SETI efforts, as well as uncover potentially interesting types of astrophysical variability. In this session we will explore the potential of optical SETI with TESS, discussing data processing efforts, challenges in variability classification, an, ultimately, what we might expect to observe if advanced life is common.
schedule: Wednesday, 14:47 UT / 10:47 ET (splinter talk)
Marlee Rapp
(University of Michigan. but for this summer, SETI Institute as well)
Fading events in light curves are often indicative of eclipses by stellar or substellar companions, and sometimes occultations by circumstellar dust. Events that do not align with these known phenomena are candidates for technosignatures. Motivated by this possibility, we are conducting a targeted search among TESS data for such fading events, using statistical selection algorithms. With millions of TESS FFI light curves in hand, we are applying a metric called "M," a measure of a star’s tendency to deviate below its median brightness. Using known fading types such as dippers and eclipsing binary systems, we determine the expected range of M values for stars with pronounced fading events. We then use this range to identify variable stars with significant fading events. Those that appear anomalous (i.e., do not fit into known categories of astrophysical variability) will be flagged for future follow-up.
schedule: Wednesday, 14:52 UT / 10:52 ET (splinter talk)
Alex Parsells
(University of Oklahoma)
The Transiting Exoplanet Survey Satellite (TESS) launched in 2018 to observe nearly the entire sky in the optical. Our group has access to the largest collection of TESS light curves available produced by the `eleanor` pipeline from the full frame images taken every 30 minutes for TESS sectors 1 to 26. Historically, light curves have been sorted manually into different variability classes. In this project, we use supervised machine learning to automate classification of TESS light curves into existing variable star categories. Complementary to this work is an anomaly scoring project to evaluate every target's normalcy in relation to other light curves. Unusual light curves that do not fit well into known variability classes may be prime candidates for follow-up observation, either as examples of rare or unknown variable types, or even targets of potential SETI interest. Preliminary results on eclipsing binaries in the Kepler FOV classification have yielded 76% accuracy using a support vector classifier.
schedule: Friday, 14:30 UT / 10:30 ET (panel)
Susan Mullally
(STScI)
JWST will be launching at the end of 2021 and will operate at the same time as TESS. With a diverse set of spectroscopic and imaging modes, many of which operate in a time series mode, JWST offers the TESS community the opportunity to follow-up their targets in the infrared. In this talk I will highlight some of the science cases across exoplanet, solar system and stellar astrophysics that Webb will tackle in the first year of its observations. I end by reminding users of the timeline and how to get involved in JWST observations.
schedule: Friday, 13:00 UT / 09:00 ET (panel)
Róbert Szakáts
()
The Transiting Exoplanet Survey Satellite (TESS) is in orbit since 2018 April 18 and started its routine operations on 2018 July 25. In the first three years the spacecraft observed the southern ecliptic hemisphere two times (sectors 1-13 and 27-39) and the northern one time (sectors 14-26). During these observations the ecliptic plane was avoided by ∼6°, except for sectors 14-16 and 24-26 where the telescope was pointed even more farther. Despite of this, TESS allows us to observe solar system objects in great quantities. First, objects with inclination grater than 6° are expected to be observed, but considering the distance of TESS from the Sun and the distance of main belt asteroids (2-3 AU) with a few degrees of inclination, thousands of objects can be observed. This was confirmed in 2020 with the First Data Release of Bright Main-belt and Trojan Asteroids from the Southern Survey (Pál et al. 2020) where almost 10000 asteroid light curves were published. The upcoming sectors 42-46 will cover the ecliptic plane giving us the opportunity to observe tens of thousands of solar system objects. In this talk I will present a method on how to detect known asteroids or comets on TESS full frame images and how to get photometric data of them. I will show some examples of already extracted light curves of individual objects and the possible use of this data in scientific analysis.
schedule: TBA, TBA UT / TBA ET (off topic)
Thalia R Khan
(JPL)
Join two public outreach specialists and a visual strategist from NASA’s Jet Propulsion Laboratory in a discussion about how they engage the public using visual stories to communicate science, scientific data, and mission objectives. Panelists will explore the process behind some of NASA’s most well-known posters, as well as the collaborative relationship between scientists and creatives at the agency.
schedule: Wednesday, 14:57 UT / 10:57 ET (splinter talk)
Tansu Daylan
(Massachusetts Institute of Technology)
Exoplanets can have circumplanetary debris disks in the form of rings as a remnant of formation or recent impacts. Furthermore, artificial megastructures could potentially exist around exoplanets if a planetary system is inhabited by a hypothetical, technologically advanced civilization. In this context, high-precision time-series photometry of a star can be used to probe any lightcurve deviations from that generated by a transiting planet with a perfectly circular cross section. Nevertheless, a large fraction of these anomalies are expected to be manifestations of stellar variability. Towards this purpose, we collect in-transit TESS photometry of known transiting exoplanets observed by TESS. We then perform unsupervised classification and anomaly detection on these data to catalog and classify in-transit anomalies.
schedule: Wednesday, 15:15 UT / 11:15 ET (splinter talk)
Joshia Bromley
(UC Berkeley)
The deployment of exoplanet seeking telescopes such as Kepler and TESS has provided a new avenue for SETI searches: anomalous transits. With the discovery of novel variable objects such as Boyajian’s star, the possibility of artificial occulting megastructures has come to the forefront. We are examining the possibility that an intelligent extraterrestrial civilization could use megastructure transits to signal its own existence. An artificial megastructure with a distinct, non-natural shape could produce a signal that, when viewed from Earth, is different from the light curves produced by exoplanets and other known astrophysical phenomena. To determine whether anomaly detection algorithms could identify such light curves from artificial sources, we are running simulations of a variety of megastructure transit shapes. We inject these ‘signal’ curves into quiet TESS light curves with no known variability. We randomly select a location to inject our anomalous transit into the TESS data. To explore the limits of our anomaly detection algorithms, we simulate shapes with a number of parameters including number of sides, rotation angle relative to the plane of Earth’s view, ratio of the height to width, the shape radius, and occulter velocity. We will report here on tests to recover these artificial signals with machine learning routines.
schedule: Wednesday, 15:05 UT / 11:05 ET (splinter talk)
Daniel Giles
(The SETI Institute)
Brightness variations of stellar sources encode a diverse range of phenomena from utbursts and explosions, to exoplanetary transits, to asteroseismic pulsations, to as yet undetermined physics. In perhaps the most interesting possibility, if there are other advanced civilizations in the galaxy, we may even be able to detect “technosignatures” in unique variability signatures. Big datasets, like that of the 60+ million light curves generated from the full frame images of the primary Transiting Exoplanet Survey Satellite (TESS) mission, present challenges to the discovery process for such types of data of interest. In this work, we present an outlier scoring methodology to identify and characterize the most unusual sources to facilitate discoveries of such anomalous data. We have developed a data mining method based on k-nearest neighbour distance in feature space to efficiently identify the most anomalous light curves and we demonstrate that a higher anomaly score corresponds to rarer forms of astrophysical variability and the most egregious data artifacts. We further outline additional machine learning approaches which are applied to a subset of the original dataset based on the derived anomaly scores, providing significant performance and predictive improvements over a mass application to all available data.
schedule: Monday, 13:35 UT / 09:35 ET (invited overview)
Roland Vanderspek
(MIT)
I will review the status of the TESS spacecraft, instrument, and operations. I will also discuss current observations and those in a potential second Extended Mission.
schedule: Monday, 13:10 UT / 09:10 ET (invited overview)
George Ricker
(MIT)
In this talk, I will summarize the current status and a sample of the exciting results from the TESS mission. As we jointly celebrate the scientific results from TESS since its launch in 2018, I will also describe some of the plans underway for TESS’s next extended mission in 2022-2025, as well as possible longer term searches with TESS in the coming decade(s).
schedule: Wednesday, 14:37 UT / 10:37 ET (splinter talk)
Jeroen Audenaert
(KU Leuven, Institute of Astronomy)
The TESS Data for Asteroseismology (T’DA) stellar variability pipeline aims to classify the tens of millions of stars observed by the TESS mission. The pipeline first performs a top-level classification using a stacked ensemble of classifiers to predict the general variability classes. In the next step we then run a clustering algorithm on each of the general variability classes in order to unravel the substructure. This allows us to identify potential misclassifications and search for new subgroups of variables stars within the predefined general variability classes. In this way we take advantage of the existing knowledge on stellar variability while still leaving room to detect new (sub-)groups of variable stars. In this talk we will focus on the clustering methodology.
schedule: Thursday, 20:00 UT / 16:00 ET (splinter talk)
Thomas Mikal-Evans
(MIT)
The TESS survey is a major component of the atmospheric characterization agenda for this decade and beyond. By staring continuously for 27 days per sector and more or less covering the entire sky, TESS is able to find many transiting planets around stars bright enough for detailed atmospheric follow-up observations. Compared to previous transit surveys, TESS is especially well suited to finding sub-Neptunes and super-Earths around bright M dwarfs, many of which have equilibrium temperatures below 1000K and belong to multi-transiting systems. With most atmospheric characterization to date having focused on hot Jupiters, these latter populations represent an exciting and largely uncharted frontier. I will review some of the first follow-up efforts to characterize the atmospheres of such TESS planets, including planned observations with HST and JWST. I will also describe work that has been done to constrain red-optical emission for certain favorable targets using the TESS photometry directly. In particular, the long-stares have allowed a number of hot Jupiter phase curves to be measured, providing constraints for atmospheric albedos and heat redistribution.
schedule: Wednesday, 13:42 UT / 09:42 ET (splinter talk)
Brett Addison
(University of Southern Queensland)
Emil Knudstrup (Aarhus University)
Ian Wong (MIT)
Guillaume Hebrard (Universite Pierre \& Marie Curie)
Patrick Dorval (Leiden University)
Ignas Snellen (Leiden University)
Simon Albrecht (Aarhus University)
Aaron Bello-Arufe (Technical University of Denmark)
Jose-Manuel Almenara (Universit\'e Grenoble Alpes)
Isabelle Boisse (Aix Marseille Univ)
Xavier Bonfils (Universit\'e Grenoble Alpes)
+ 62 additional co-authors
Here I present the discovery of an ultra-hot Jupiter, TOI-1431b/MASCARA-5b, detected by TESS and MASCARA. Radial velocity measurements with SONG, SOPHIE, FIES, NRES, and EXPRES confirms the planet candidate with a reflex motion of K=294.1±1.1m/s. A joint analysis of the photometry and RVs gives TOI-1431b a mass of Mp=3.14±0.19MJ, an inflated radius of Rp=1.51±0.06RJ (16.9±0.7Re), and an orbital period of P~2.65d. The planet orbits a bright (V=8.05mag), young (~290Myr), and hot (Teff~7700K) Am type star. Using TESS photometry, we were able to measure the planet's thermal emissions in the red-optical from the full phase curve and secondary eclipse, allowing us to determine the dayside and nightside temperature of its atmosphere as Tday=2983±68K and Tnight=2556±65K. The planet's low day/night temperature contrast (~400K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness, the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as JWST and ARIEL.
schedule: Wednesday, 14:47 UT / 10:47 ET (splinter talk)
Pierre-Alexis Roy
(Universite de Montreal)
Björn Benneke, Universite de Montreal ;
Against prior expectations, the Kepler and TESS missions revealed a remarkable population of sub-Neptune exoplanets, likely representing the most common type of close-in exoplanet. Despite this, our understanding of the nature of these sub-Neptunes remains extremely limited, mainly because atmospheric clouds mute the molecular features in their transmission spectra. The recent TESS discovery of TOI-824 b opens a new window into these worlds and provides an unprecedented opportunity to study a hot and dense 2.9 Earth radii sub-Neptune via secondary eclipses. Here, we present the detection of a hot dayside on TOI-824 b via Spitzer secondary eclipse observations. We combine this detection with a renewed analysis of possible interior compositions, in which we reveal that TOI-824 b could be a "stripped Neptune": a Neptune-like planet that lost its hydrogen envelope during its migration period and residence on a 1.4-day orbit. We show that the hot dayside and poor heat redistribution around TOI-824 b would be most consistent with this stripped Neptune scenario. With TOI-824 b's possibly distinct nature and extraordinarily high Eclipse Spectroscopy Metric, TOI-824 b is the ideal target for future follow-up observations of sub-Neptunes.
schedule: Wednesday, 15:23 UT / 11:23 ET (splinter talk)
Kristine Lam
(Technische Universität Berlin)
Szilárd Csizmadia, Nicola Astudillo-Defru, Xavier Bonfils, Davide Gandolfi, Sebastiano Padovan, Massimiliano Esposito, Coel Hellier, Teruyuki Hirano, John Livingston, Felipe Murgas, Alexis M. S. Smith, Karen A.~Collins, Savita Mathur, Rafael A. Garcia, Steve B. Howell, Nuno C. Santos, Fei Dai, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Simon Albrecht, Jose M. Almenara, Etienne Artigau, Oscar Barragan, François Bouchy, Juan Cabrera, David Charbonneau, Priyanka Chaturvedi, Alexander Chaushev, Jessie L. Christiansen, William D. Cochran, José-Renan De Meideiros, Xavier Delfosse, Rodrigo F. Díaz, René Doyon, Philipp Eigmüller, Pedro Figueira, Thierry Forveille, Malcolm Fridlund, Guillaume Gaisné, Elisa Goffo, Iskra Georgieva, Sascha Grziwa, Eike Guenther, Artie P. Hatzes, Marshall C. Johnson, Petr Kabáth, Emil Knudstrup, Judith Korth, Pablo Lewin,Jack J. Lissauer, Christophe Lovis, Rafael Luque, Claudio Melo, Edward H. Morgan, Robert Morris, Michel Mayor, Norio Narita, Hannah L. M. Osborne, Enric Palle, Francesco Pepe, Carina M. Persson, Samuel N. Quinn, Heike Rauer, Seth Redfield, Joshua E. Schlieder, Damien Ségransan, Luisa Serrano, Jeffrey C. Smith, Ján Šubjak, Joseph D. Twicken, Stéphane Udry, Vincent Van Eylen, Michale Vezie
Ultra-Short-Period (USP) planets have orbital periods shorter than one day and their origin is still unknown. Measuring their precise masses and radii gives important constraints to probe the formation and evolution of USP planets, and how their atmospheres behave under extreme stellar irradiation. Here we report the discovery of GJ 367b, a USP sub-Earth sized planet orbiting one of the brightest, nearby M dwarf every 7.7 hours. The planet has a radius of 0.718 +- 0.054 Earth-radii and a mass of 0.546 +- 0.078 Earth-masses. The sub-Earth sized planet is the least massive known USP with a precise mass determination. Its bulk density of 8.106 +- 2.165 g/cm^3 suggests an iron-rich interior which is similar to that of Mercury’s.
schedule: Wednesday, 15:11 UT / 11:11 ET (splinter talk)
Luca Malavolta
(Università degli Studi di Padova)
Samuel N. Quinn (Center for Astrophysics)
Thomas G. Wilson (University of St Andrews)
HARPS-N GTO Science Team and Collaborators
Super-Earths with periods shorter than one day are usually referred as Ultra-Short Period planets. Some of them orbit the host star so closely that the surface temperature can reach several thousand degrees, and the thermal emission of the day side can be detected photometrically in the same light curve used to discover the planet. The HARPS-N GTO collaboration has been pivotal in measuring the mass and internal density of these so-called lava worlds detected by Kepler, K2, and now TESS. After briefly reviewing the most important lava worlds, in this proposed talk I will describe our efforts to characterize TOI-2431, a rocky planet orbiting a bright (V=10.9) K dwarf every 5.4 hours, the shortest period among planets with a known density. The planet is expected to have lost its primordial atmosphere, but it may well possess a rock vapor atmosphere sustained by its surface magma ocean. For its short orbital period and the brightness of the host star, this is so far the best target for the characterization of the molten surface of an exo-world using current and future facilities such as CHEOPS, Hubble, and James Webb Space Telescopes.
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter talk)
Ian Wong
(MIT)
We present the discovery of the extreme ultra-hot Jupiter TOI 2109b. The planet was detected from the TESS Full Frame Images in Sector 25 and lies on a 0.67-day orbit around a V=10.2 mag F-type star. Follow-up photometry and high angular resolution imaging confirmed the transit signal on target, and stellar spectra obtained from TRES revealed a rapidly rotating host star (vsini~80 km/s). We measured a planet mass of 4.8 Mjup from radial velocities. Doppler tomographic transit observations from TRES definitively excluded all false positive scenarios and uncovered a large obliquity (λ ~ –50°). The TESS photometry displays a high signal-to-noise phase curve and secondary eclipse, as well as periodic stellar variability at the ~200 ppm level. We combined the TESS-band secondary eclipse depth with a Ks-band secondary eclipse measurement from Palomar and obtained a dayside brightness temperature of ~3900 K, making TOI 2109b the second-hottest gas giant discovered so far. The planet is highly amenable to intensive atmospheric characterization with both ground- and space-based facilities, and the strong planet-star tidal interaction makes TOI 2109b a particularly promising candidate for studying tidal decay and atmospheric mass loss.
schedule: Wednesday, 14:30 UT / 10:30 ET (splinter talk)
Alexander Patrick Stephan
(The Ohio State University)
Prof. Smadar Naoz (UCLA, Prof. Scott Gaudi (OSU)
Since the launch of TESS, several Hot Jupiters orbiting evolved stars, at various stellar evolution stages, have been discovered. Many of these planets present a challenge from a planetary and tidal evolution perspective, as they should have been destroyed a long time ago, if they were present at their current orbital configurations early in their host stars' lifetimes. However, these planets may instead have remained on wide orbits for most of their host stars' lifetime, only undergoing high-eccentricity tidal migration once those stars expanded towards the end of the main-sequence, which increases the efficiency of tidal dissipation. As I will show in this talk, the Eccentric Kozai-Lidov (EKL) mechanism, triggered by a distant stellar or planetary companion, is perfectly suited to trigger such migration. Furthermore, this mechanism implies the existence of "Temporary" Hot Jupiters, which only register as Hot Jupiters for a relatively short time before being engulfed by their still evolving star, with important implications for the rotation rates and envelope structures of post-main sequence stars.
schedule: Wednesday, 14:15 UT / 10:15 ET (splinter talk)
Andreas Hadjigeorghiou
(University of Warwick)
Dr. David Armstrong, University of Warwick; Ares Osborn, University of Warwick
Presenting the ongoing development of RAVEN (RAnking and Validation of ExoplaNets), an automated vetting and validation pipeline for TESS exoplanet candidates. The pipeline uses Machine Learning (ML) algorithms to separate planetary candidates from False Positives (FP). The ML models are trained on a synthetic training set of TESS lightcurves, where simulated transits of planets and astrophysical FPs have been injected. The ML classification score is then combined with pre-computed prior probabilities for the planet and all FP scenarios to calculate their posterior probability. Candidates with a probability greater than 99% to be a planet are statistically validated. Since posterior probabilities will be calculated for all candidates, our results can be used to rank and prioritise candidates for valuable follow-up observations and even inform planetary occurrence calculations. The pipeline will be applied on lightcurves extracted from the Full Frame Images, for stars down to mangitude 13.5, allowing us to simultaneously find and validate planets out of about 13M stars. This talk provides an overview of the project, its development progress and the potential science outcomes.
schedule: Wednesday, 14:45 UT / 10:45 ET (splinter talk)
Claudia Reyes
(University of New South Wales)
Dennis Stello, University of New South Wales; Marc Hon, University of Hawai‘i
Near all-sky asteroseismology with TESS is the new frontier in Galactic archeology studies. To determine the masses, radii, and ages for the hundreds of thousands of Sun-like stars observed by TESS, it is critical that reliable measurements of the seismic large frequency separation, Delta_nu, can be verified. Although numerous seismic pipelines provide measurements of Delta_nu, the vetting of such measurements have been a major bottleneck in previous ensemble asteroseismic analyses. Here, we present a machine learning approach to automatically vet reliable measurements of Delta_nu irrespective of the seismic pipeline that provided the measurement. We apply our method to seismic data from the K2 Galactic Archeology program and show that with minimal manual analysis, we can easily recover the most reliable seismic measurements that are consistent with measurements taken from a consensus across all seismic pipelines. Our upcoming algorithm will be published as open-source code and designed to be easily added on to existing tools like Lightkurve or PySYD.
schedule: Wednesday, 13:30 UT / 09:30 ET (splinter talk)
Zoe L. de Beurs
(University of Texas at Austin)
Andrew Vanderburg [1], Christopher J. Shallue [2], Joseph E. Rodriguez [3], Sebastian Zieba [4], Annelies Mortier [5, 6], Lars Buchave [7], Luca Malavolta [8], and the HARPS-N Collaboration
Affiliations
1. Department of Astronomy, University of Wisconsin-Madison, Madison, WI, 53706, USA
2. Center for Astrophysics | Harvard & Smithsonian (CfA), 60 Garden St., Cambridge, MA 02138, USA
3. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
4. Max-Planck-Institut für Astronomie (MPIA), Königstuhl 17, 69117 Heidelberg, Germany
5. Astrophysics Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
6. Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
7. DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 328, DK-2800 Kgs. Lyngby, Denmark
8. Dipartimento di Fisica e Astronomia ``Galileo Galilei'', Università di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova, Italy
We report precise radial velocity observations of HD 212657 (= K2-167), a star shown by K2 to host a transiting planet in a 9.97857 day orbit. Using observations from TESS, we refined planet parameters, especially the orbital period. We collected 76 precise radial velocity observations with the HARPS-N spectrograph between August 2015 and October 2016. Although this planet was first found using the transit method in 2015 and validated in 2018, stellar jitter originally limited our ability to measure its mass. In this work, we demonstrate that a new machine learning inspired method can successfully mitigate stellar jitter and reveal the mass of K2-167 b. In the future, these or similar techniques could be widely applied to solar-type (FGK) stars, help measure masses of planets from TESS to fulfill the level 1 science requirement, and eventually help detect habitable-zone Earth-mass exoplanets.
schedule: Wednesday, 13:45 UT / 09:45 ET (splinter talk)
Adrien Leleu
(Université de Genève)
A. Leleu$^{1,2}$,
Y. Alibert$^{2}$,
N. C. Hara$^{1}$,
M. J. Hooton$^{2}$,
T. G. Wilson$^{3}$,
P. Robutel$^{4}$,
J.-B. Delisle$^{1}$,
J. Laskar$^{4}$,
S. Hoyer$^{5}$,
C. Lovis$^{1}$,
E. M. Bryant$^{6,7}$,
E. Ducrot$^{8}$,
J. Cabrera$^{9}$,
L. Delrez$^{8,10,1}$, et al
$^{1}$ Observatoire Astronomique de l'Universit\'e de Gen\`eve, Chemin Pegasi 51, Versoix, Switzerland\\
$^{2}$ Physikalisches Institut, University of Bern, Gesellsschaftstrasse 6, 3012 Bern, Switzerland\\
$^{3}$ Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK\\
$^{4}$ IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ., Sorbonne Univ., 77 av. Denfert-Rochereau, 75014 Paris, France\\
$^{5}$ Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France\\
$^{6}$ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK\\
$^{7}$ Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK\\
$^{8}$ Astrobiology Research Unit, Universit\'e de Li\`ege, All\'ee du 6 Ao\^ut 19C, B-4000 Li\`ege, Belgium\\
$^{9}$ Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany\\
$^{10}$ Space sciences, Technologies and Astrophysics Research (STAR) Institute, Universit{\'e} de Li{\`e}ge, All{\'e}e du 6 Ao{\^u}t 19C, 4000 Li{\`e}ge, Belgium\\
Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. As unveiled by TESS, CHEOPS, ESPRESSO, NGTS and SPECULOOS, TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, all planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet. TOI-178 have hence several characteristics that were not previously observed in a single system, making it a key system for the study of processes of formation and evolution of planetary systems. We will review what we know of TOI-178, and what we expect from futur observations.
schedule: Wednesday, 14:15 UT / 10:15 ET (splinter talk)
Dominic Oddo
(University of New Mexico)
Diana Dragomir - University of New Mexico
TESS has searched the entire sky for transiting exoplanets around the nearest, brightest stars, and the planets it has and will discover have the potential to gradually populate the small planet mass-radius parameter space with tightly constrained bulk densities, which are vital pieces to improving our understanding of the radius valley at 1.5-2.0 Earth radii and how it is shaped by atmospheric mass-loss processes. We present precise radius measurements and orbital parameters for five TOIs with estimated radii from 1.3 to 4.3 Earth radii, which have been observed by CHEOPS, which has a larger light-collecting area compared to TESS, allowing for exquisite characterization of the targets. Transits obtained by CHEOPS not only allow for the radius of these targets to be constrained, but also other orbital parameters such as eccentricity, which allow us a closer glimpse into the architectures of these systems. We compare CHEOPS and TESS parameters for these TOIs, and search for any changes in transit depth that may be indicative of atmospheric features (i.e. Rayleigh scattering).
schedule: Wednesday, 15:21 UT / 11:21 ET (splinter talk)
Gaia Lacedelli
(University of Padova)
Well-characterized multiplanetary systems offer a unique opportunity for comparative planetology, allowing for investigations of the formation and evolution processes. I will present the analysis of a new multiplanetary system, TOI-561, initially discovered by the TESS mission through photometric observations, and further characterized using high-precision RV data collected with the HARPS-N spectrograph, that allowed us to obtain precise masses for all the four planets in the system, namely an ultra-short period super-Earth and three mini-Neptunes (Lacedelli et al. 2020). I will show how in this case combining photometric and RV data has been essential to discriminate between various possible architectures, highlighting the importance of combining different techniques to obtain a better characterization of a planetary system. Additional insights on the planetary architecture and internal structure are coming from the ultra-high precision photometry of the CHEOPS satellite, which additionally stresses the importance of synergies between various techniques and instruments.
schedule: Wednesday, 15:24 UT / 11:24 ET (splinter talk)
Thomas Wilson
(University of St Andrews)
The study of multi-planet systems can reveal important aspects that challenge our knowledge of planet formation and evolution via determination of planetary system architectures and internal structures. The CHEOPS satellite, launched in Dec 2019, has spent the past year taking high-precision transit photometry of such systems with a key science goal of the mission to further our understanding of this sub-field of exoplanet research.
In this talk, I will present work done to characterise multi-planet systems initially discovered with TESS and followed-up with CHEOPS in order to accurately refine the planetary radii. Additionally, when these data are combined with radial velocity observations, we can infer a range of physical properties about the planets via internal structure and atmospheric escape modelling. Therefore, I will also present the results of utilising such models on these mutli-planet systems. Key knowledge about these systems was uncovered via precise follow-up observations with CHEOPS, that underlines the importance of the synergy between detection and accurate follow-up missions.
schedule: Wednesday, 14:45 UT / 10:45 ET (splinter talk)
Faith Hawthorn
(University of Warwick)
Daniel Bayliss (University of Warwick), David Armstrong (University of Warwick, NCORES project), et al.
We present the discovery of two exoplanets transiting TOI-836 using data from TESS sector 11. TOI-836 is a bright, high proper motion K-dwarf with a mass of 0.7 Solar masses and a radius of 0.7 Solar radii. The outer planet is a mini-Neptune in an 8.59 day orbit, and the inner planet is a super-Earth in a 3.82 day orbit. Planetary masses are determined via radial velocity measurements from the HARPS NCORES program, in addition to radial velocity measurements from other facilities. Follow-up photometric observations with NGTS, MEarth, LCO and CHEOPS show transiting timing variations on the order of 15 minutes, which is consistent with expectations given the radial velocity measured masses.
poster number: 1.01 | zenodo
Aidan Van Duzer
(Massachusetts Institute of Technology (MIT))
Aidan Van Duzer1, Maximilian N. Günther1,*, Natalia Guerrero1, Tansu Daylan1,†
1 Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
* Juan Carlos Torres Fellow
† Kavli Fellow
Inspiring the next generation of astronomers is an essential element of the TESS mission. However, in classroom or outreach settings, limited computing tools and programming knowledge can pose barriers to hands-on experiences. Allesfitter, a software package to analyze and model data from TESS and other missions, can provide an inclusive educational tool to engage students and public audiences. By hosting and running Allesfitter in the cloud in an easy-to-use Jupyter Notebook graphical interface, learners can model TESS light curves without prior coding knowledge or software installation, unveiling real astronomical events such as exoplanet transits or binary systems. A learner’s individual experience of modeling state-of-the-art TESS data, coupled with an instructor’s guidance, gives a compelling, visual insight into the exciting world of astronomy. Expanding Allesfitter’s usage into the classroom can help inspire a new generation to engage with public data from TESS and other missions.
poster number: 1.02 | zenodo
Ashley Chontos
(Institute for Astronomy, University of Hawai'i at Mānoa)
Daniel Huber, Institute for Astronomy, University of Hawai'i at Mānoa
Maryum Sayeed, Institute for Astronomy, University of Hawai'i at Mānoa
Asteroseismology is well-established in astronomy as the gold standard for determining precise and accurate fundamental stellar properties like masses, radii, and ages. Several tools have been developed for asteroseismic analyses, but nearly all of them are closed-source and therefore not accessible to the general astronomy community. Here we present pySYD, a Python package for detecting solar-like oscillations and measuring global asteroseismic parameters. pySYD was adapted from the IDL-based SYD pipeline, which was extensively used to measure asteroseismic parameters for Kepler stars. pySYD was developed using the same well-tested methodology, but has improved functionality including automated background model selection and parallel processing as well as improved flexibility through a user-friendly interface. Well-documented, open-source asteroseismology software that has been benchmarked against closed-source tools are critical to ensure the reproducibility of legacy results from the Kepler mission.
poster number: 1.04 | zenodo
Emma Chickles
(MIT)
Tansu Daylan (MIT), Lindsey Gordon (University of Minnesota)
Stellar variability is driven by various processes occurring at the stellar surface and in the stellar interior, such as due to stellar eclipses, flares, tidal interactions, pulsations, spots, and rotation. We use unsupervised machine learning on photometric light curves observed by the Transiting Exoplanet Survey Satellite (TESS) to conduct a census of different types of stellar variability. Towards this purpose, we use a one-dimensional convolutional autoencoder and feature engineering, which yields compressed, low-dimensional representations of the data. We use the learned representations to perform large-scale classification and novelty detection using TESS light curves. We validate our pipeline using cataloged eclipsing binaries in ASAS-SN, the General Catalogue of Variable Stars, and SIMBAD. The indiscriminate survey produced by TESS offers a unique opportunity to investigate the relationships between light curve features and underlying stellar characteristics such as type, age, metallicity, and mass. Our homogeneous census of stellar variability will lead to a better understanding of the underlying demographics.
poster number: 1.05 | zenodo
Erin Howard
(Western Washington University)
James R.A. Davenport - University of Washington
Kevin R. Covey - Western Washington University
Developing effective machine learning training labels can be a time consuming task if done manually, particularly for a classification that has many representations. This manual classification task takes even longer when only a small portion of the data contains the desired class. Utilizing statistical analysis to pre-classify a portion of the data can potentially lessen the burden of manually classification and provide more effective scientific outcomes than manual classification alone. However, this method has not been heavily utilized in research. Using data from TESS as a use case, we applied a binary statistical classification to ~275,000 light curves (LCs) to determine whether each curve contains an eclipse. After the first round of statistical classification, we restricted our inspection to all observations of any object that had at least one eclipse observed. This gave us ~6,000 LCs to manually classify, which resulted in a label set that included a balanced variety of eclipses---labeled as an eclipsing binary (EB)---and non-eclipses---labeled non-EBs. The statistical analysis was able to complete its classification of over 275k LCs in less than ten hours, reducing time spent manually classifying.
poster number: 1.06 | zenodo
Gavin Wang
(Stanford Online High School)
Karen Collins, Harvard-Smithsonian Center for Astrophysics
After follow-up, many TESS Objects of Interest are found to be nearby eclipsing binaries. In this scenario, a pair of binary stars visually close to the target star produces photometric signals that are mistaken for those produced by a transiting planet. Identifying such false positives through follow-up observations allows future observing resources to be focused on the remaining active TOIs. Yet, on the other hand, data that reveals a false positive will likely never be published. As such, it is beneficial to rule out false positives, if possible, before follow-up observing resources have been spent on them. Despite TESS’s large pixel scale of 21”, it is possible to identify NEBs for which the target star and the binary are separated by more than ~30” using the TESS full-frame images. In this project, we used AstroImageJ to reduce FFIs and searched for NEBs in a sample of 34 TOIs. This sample contains targets whose QLP reports show hints of NEBs, which include centroid offsets and depth-aperture correlation, as well as secondary transits for candidates with nominally small planet radii. Among these candidates, 10 were found to be NEBs and are now retired. It is estimated that these results have saved ~30 hours of telescope time.
poster number: 1.07 | zenodo
Gregory Snyder
(Space Telescope Science Institute)
Susan Mullally, Geert Barentsen (NASA Ames), Scott Fleming, Joshua Peek, Ivelina Momcheva, Andrew Cortese, Michael Gough, Brian Hayden, Ru Kein, Jacob Matuskey, Todd Miller, Christine Slocum, Michael Fox (all affiliations STScI unless noted)
We present a Beta version of the Timeseries Integrated Knowledge Engine (TIKE) Science Platform, a JupyterHub service for accessing and analyzing cloud-hosted data products at the Mikulski Archive for Space Telescopes (MAST). To support high-throughput access to TESS mission data, MAST hosts a copy of its collection in Amazon Web Services (AWS). As of early 2021, these products are freely and anonymously accessible without an AWS account.
TIKE provides a user-friendly, Python-focused computing environment for engaging with these datasets from within AWS, for both beginners and experts. As astronomical survey data volumes grow, they become more accessible if we can bring scientists to data in addition to providing tools to transfer data to scientists.
TIKE benefits include high data throughput between the TESS data in AWS and TIKE computing, introductory documentation and tutorials, as well as a Python environment pre-installed with 20+ community software packages. These include both core software such as Astropy, Tensorflow, and Matplotlib, plus timeseries-focused packages such as Eleanor, Everest, Lightkurve, and others.
poster number: 1.08 | zenodo
Jaide Swanson
(University of Washington)
Keaton Bell, University of Washington
Large TESS pixels typically capture light from multiple stars, and the data processing pipeline subtracts the estimated contributions of contaminant stars from the light curves it produces. If these crowdedness factors (recorded as the header keyword CROWDSAP) are not exact, they will cause systematic errors on measurements of transit depths and variability amplitudes. We are performing an independent determination of estimated CROWDSAP factors by comparing the depths of binary eclipses between TESS light curves and ground-based data from ASAS-SN with a Markov Chain Monte Carlo analysis. This allows us to accurately appraise the precision of pipeline CROWDSAP factors, the uncertainty on which should be incorporated into TESS analyses as an extrinsic error.
poster number: 1.09 | zenodo
John Kielkopf
(University of Louisville)
The high performance Julia Programming Language (https://julialang.org/) is an open source project offering pre-built binaries that run on most commonly used platforms. With similarities to Python and Matlab that are commonly used for astrophysical data analysis, it is easy for experienced students and programmers to learn, and to adapt existing code, or to import code from other languages using its native tools. Although comprehensive libraries similar to astropy are not available, essential ones such as FITS file procedures, are supported. We have experimented with Julia for the analysis of TESS data in cases where the speed of Python is limiting: transit modeling and fitting, and processing of time series stacks of TESS Full Frame Images. This poster highlights the features of Julia programming, contrasts those against the familiar Python and Matlab languages, and compares the outcomes for test cases. These results demonstrate a significant decrease in processing time with Julia for large data arrays where broadcasting methods enable operations on many elements simultaneously.
poster number: 1.10 | zenodo
Keaton J. Bell
(University of Washington)
Python has become the de facto standard programming language for astronomical research, with many open-source packages available for accessing, manipulating, and visualizing photometric time series data from Kepler, K2, and TESS. However, specialized tools for fitting frequency solutions to these time series have been conspicuously absent, causing many researchers to rely on closed-source legacy software, such as Period04. This live tutorial demonstrates the use of the new Pyriod package for the pre-whitening analysis of time series photometry of pulsating stars that fills this gap in the modern Python workflow for time domain stellar astrophysics. Pyriod can be used either interactively with Jupyter Notebook widgets, or through direct access to functions for automated analyses. It can also be easily extended by the user to provide additional functionality as desired.
poster number: 1.11 | zenodo
Peter Klagyivik
(DLR (Berlin, Germany))
Computer vision is a field of artificial intelligence that deals with how computers can gain understanding from digital images or videos. From another perspective, it seeks to understand and automate tasks that the human visual system can do. Computer vision tools are already in use for galaxy search and classification, or comet search. Finding transiting planet candidates looking at the photometric light curves is easy for humans, therefore they should be detectable with computer vision methods. However, first the time-series data must be somehow encoded into 2D images. I present a pilot study of transiting planet search with computer vision using Convolutional Neural Network and its application on TESS Sector 1 short cadence light curves.
poster number: 1.12 | zenodo
Ryan Ridden-Harper
(Johns Hopkins University)
Armin Rest, Space Telescope Science Institute
Rebekah Hounsell, University of Maryland, Baltimore County + Godard Space Flight Centre
Tomás Müller-Bravo, University of Southampton
Qinan Wang, Johns Hopkins University
TESSreduce is a streamlined, pip installable, forced photometry pipeline to easily produce reliable TESS lightcurves, specializing in transients. Built on a Lightkurve foundation (Lightkurve Collaboration 2018), TESSreduce can reduce and calibrate any TESS target pixel file, such as those generated by TESScut, allowing for easy analysis of all TESS data. With TESSreduce, data collection, background subtraction, difference imaging, flux calibration, comparison with ground-based data, and many other functions can be done in just a few lines, making transient science with TESS more accessible for everyone! Getting a TESS light curve is as simple as: import tessreduce as tr tess = tr.tessreduce(ra,dec,sector)
poster number: 1.13 | zenodo
Adam Rains
(Australian National University)
Adam D. Rains (Australian National University)
Maruša Žerjal (Australian National University)
Michael J. Ireland (Australian National University)
Thomas Nordlander (Australian National University, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions)
Michael S. Bessell (Australian National University)
Luca Casagrande (Australian National University, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions)
Christopher A. Onken (Australian National University, Centre for Gravitational Astrophysics)
Meridith Joyce (Australian National University, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions)
Jens Kammerer (Australian National University, European Southern Observatory)
Harrison Abbot (Australian National University)
We present the results of a medium resolution optical spectroscopic survey of 92 cool (3,000 < Teff < 4,500 K) southern TESS candidate planet hosts for which we determine stellar parameters and activity measures. Our fitted Teff and stellar radii have median precisions of 0.8% and 1.7%, respectively and are consistent with our sample of benchmark stars. We use these parameters to model the TESS transit light curves and determine exoplanet radii for 100 candidate planets to 3.5% precision, and see evidence that the planet-radius gap is present for the TESS sample of cool dwarfs. Our results are consistent with the sample of confirmed TESS planets, with this survey representing one of the largest uniform analyses of cool TESS candidate planet hosts to date.
poster number: 1.14 | zenodo
Adina Feinstein
(University of Chicago)
Benjamin Montet, University of New South Wales
Marshall Johnson, Las Cumbres Observatory
Jacob Bean, University of Chicago
Trevor David, Center for Computational Astrophysics, Flatiron Institute
Michael Gully-Santiago, The University of Texas at Austin
John Livingston, University of Tokyo
Rodrigo Luger, Center for Computational Astrophysics, Flatiron Institute
Young transiting exoplanets (< 100 Myr) provide crucial insight into atmospheric evolution. However, detailed transmission spectroscopy and measuring atmospheric mass loss is made even more challenging due to the general increased activity and prominent disk inhomogeneities present on young stars. Here, I will present spectroscopic observations of V1298 Tau c, a 5.59 REarth planet orbiting a 23 Myr solar analogue discovered in K2 Campaign 4. Through detailed analysis, we find evidence that V1298 Tau c is transiting at an active latitude. Additionally, we find that H-alpha smoothly decreases during the transit. While this could be a tentative detection of an extended young atmosphere, we find this variation is consistent with other young stars observed over six hours. During the 2nd year of the extended mission, TESS will be visiting V1298 Tau during two sectors. These new TESS light curves will show much lower variability amplitudes by virtue of spot contrast that will allow us to further characterize the transit depths for all planets in the system, update ephemerides, and search for transit timing variations. Additionally, we may be able to constrain the orbital period of V1298 Tau e, which was a single transit detection in K2.
poster number: 1.15 | zenodo
Akash Gupta
(UCLA)
Akash Gupta, UCLA; Hilke E. Schlichting, UCLA, MIT
Observations have revealed a lack of planets of sizes ~1.5-2.0 Earth radii, i.e. a radius ‘valley’ or ‘gap’ in the size distribution of small, short-period exoplanets. This observation has been typically attributed to atmospheric mass-loss due to photoevaporation. However, in recent work, Ginzburg et al. (2018) and Gupta and Schlichting (2019, 2020) have demonstrated that atmospheric mass-loss, powered by the cooling luminosity of a planet and its host star’s bolometric luminosity, can also explain the origin of this radius valley, even in the absence of photoevaporation or any other process. In my talk, I will describe the key physical processes that drive this core-powered mass-loss mechanism followed by a comparison of our results with observations and the testable predictions we can make for the distribution of planets as a function of planet and host star properties. Finally, I will discuss our latest work where we present lists of planets that could be undergoing considerable atmospheric mass-loss or that might harbor secondary atmospheres abundant with high-molecular weight species, low-density interiors or both, if their evolution is indeed primarily dictated by core-powered mass-loss.
poster number: 1.16 | zenodo
Alex Hindle
(Newcastle University)
Prof. T. M. Rogers, (1) School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK; (2) Planetary Science Institute, Tucson, AZ 85721, USA
Dr. P. J. Bushby, (1) School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
Recent westward hotspot/brightspot offset measurements present significant exceptions from the norm of eastward hotspots found in the general hot Jupiter population. If these signals are to be trusted, they cannot be explained by hydrodynamic theory of synchronously rotating hot Jupiters, which predicts hotspots are always recirculated eastward of the substellar point. However, 3D magnetohydrodynamic (MHD) simulations predicted westward hotspot offsets would be possible in the hottest hot Jupiters (ultra-hot Jupiters). This is consistent with the emerging observational evidence as four out of the five westward measurements have been made on ultra-hot Jupiters, including one using TESS. Until now, however, the MHD mechanism that can drive such reversals has not been well understood. This talk will cover the findings of two recently submitted papers regarding the magnetic reversal mechanism. In the first part we will identify MHD mechanism responsible for hotspot reversals. In the second part, will physical consequences of the mechanism and apply a physically-motivated reversal criterion to a hot Jupiter dataset. Consequences include observational constraints of magnetic fields strengths and testable predictions that TESS can probe.
poster number: 1.17 | zenodo
Alexander James Mustill
(Lund University)
Michiel Lambrechts (Lund University); Melvyn B Davies (Lund University)
The properties of a planetary system may be influenced by properties of the host star, such as its birth environment or age. Recently, a link has been found between a star's local phase space density in the Galaxy and the presence of a hot Jupiter: hot Jupiters are preferentially found around stars with higher local phase space densities. Using kinematic data for exoplanet hosts from Gaia EDR3, we show that the phase space density is primarily determined by a star's Galactic kinematics -- notably, its orbital velocity around the Galactic centre relative to a circular orbit. Stars on kinematically "colder" orbits have higher local phase space densities than stars on kinematically "hotter" orbits. Once this effect is accounted for, we find no evidence that hot Jupiter hosts are in higher-density regions of phase space than other stars. Younger stars are on average on colder orbits, and older stars are on average on hotter orbits, so we argue that the preference for hot Jupiter hosts to be in high-density regions reflects an age bias: hot Jupiters are more common around younger stars, before their population is reduced by tidal inspiral. Our submitted paper is available as a preprint at https://arxiv.org/abs/2103.15823
poster number: 1.18 | zenodo
Alexander Venner
(None)
Alexander Venner (No Affiliation), Andrew Vanderburg (University of Wisconsin-Madison), Logan A. Pearce (University of Arizona)
Radial velocity surveys have uncovered a growing number of long period (>5 year) giant exoplanets in recent years, but measuring the orbital inclinations of these objects remains challenging. Gaia will provide inclinations and true masses for many of these long-period companions, but this data is not yet available. However, combining proper motion data from Gaia and the earlier Hipparcos mission allows for measurements of orbital inclinations in favourable cases. We highlight examples where Hipparcos-Gaia astrometry provides constraints on mutual inclinations in systems that also include transiting planets, such as the π Mensae system. We also discuss systems with transiting planets where astrometric accelerations suggest the presence of unidentified long-period companions. Lastly we discuss cases where Hipparcos-Gaia astrometry reveals that supposed long-period planets are not planets at all, but are instead stars or brown dwarfs observed at near-polar orbital inclinations. These results provide a dress rehearsal for the full release of Gaia astrometry which will provide constraints for comparatively lower mass planets at shorter orbital periods, providing deep constraints on the architectures of exoplanetary systems.
poster number: 1.19 | zenodo
Allyson Bieryla
(Center for Astrophysics | Harvard & Smithsonian )
René Tronsgaard Rasmussen (National Space Institute, Technical University of Denmark), Lars A. Buchhave (National Space Institute, Technical University of Denmark), David W. Latham (Center for Astrophysics | Harvard and Smithsonian), Guillermo Torres (Center for Astrophysics | Harvard and Smithsonian), Jason D. Eastman (Center for Astrophysics | Harvard and Smithsonian), Samuel N. Quinn (Center for Astrophysics | Harvard and Smithsonian), , Daniel A. Yahalomi (Columbia University), Jessica Mink (Center for Astrophysics | Harvard and Smithsonian), Gilbert Esquerdo (Center for Astrophysics | Harvard and Smithsonian), Michael Calkins (Center for Astrophysics | Harvard and Smithsonian), Perry Berlind (Center for Astrophysics | Harvard and Smithsonian)
The Tillinghast Reflector Echelle Spectrograph (TRES) is a fiber-fed optical spectrograph with a resolution of 44,000. TRES is a workhorse for recon spectroscopy as part of the TESS Follow-up Observing Program (TFOP). To date, over 2500 spectra of over 1000 TOIs have been obtained with TRES. In addition, over 200 TOIs have been observed with the Fiber-fed Echelle Spectrograph (FIES). These spectra are carefully examined to search for possible false positives such as double-lined spectra or targets that show large velocity variation indicating a stellar companion. The spectra are also used to derive stellar parameters using the Stellar Parameter Classification (SPC) tool. Extracted spectra along with quick-look stellar classification plots from the TRES pipeline are uploaded to ExoFOP-TESS weekly to encourage community collaboration. A full SPC analysis of all TRES and FIES spectra is being run to provide effective temperature, surface gravity, projected rotational velocity and metallicity. A quality flag indicator will also be applied to the classifications based on the quality of the data and the stellar type/parameters. These parameters will be uploaded to ExoFOP-TESS once the analysis is complete for community use.
poster number: 1.20 | zenodo
Amy Tuson
(University of Cambridge)
Didier Queloz, University of Cambridge & University of Geneva
Hugh Osborn, MIT & University of Bern
Solène Ulmer-Moll, University of Geneva
Monika Lendl, University of Geneva
The Transiting Exoplanet Survey Satellite (TESS) observed the majority of the sky for only 27 days during the primary mission and therefore revealed a large population of monotransits – planet candidates only observed to transit once in the data. Thanks to the TESS extended mission, the sky is being reobserved and simulations predict that a large fraction of the monotransit candidates will be observed to transit a second time. An automated pipeline is being developed to search for these so-called duotransits which are characterised by two transits separated by approximately two years. The most astronomically interesting of the duotransits discovered by this pipeline will be followed-up by the CHaracterising ExOPlanets Satellite (CHEOPS), in order to determine their periods and confirm their planetary nature. This offers the exciting opportunity to discover long-period transiting exoplanets, amenable to radial velocity follow-up and future atmospheric characterisation.
poster number: 1.21 | zenodo
Ancy Anna John
(University of St Andrews)
Andrew Cameron(University of St Andrews)
After the detection of exoplanets using TESS, a major hurdle in the mass characterisation of these bodies with follow-up radial velocity(RV) observations is the contamination due to spurious stellar activity signals, as it is challenging to differentiate between a signal induced by stellar activity and a planet. A new algorithm, SCALPELS, has been developed to separate RV Doppler shifts caused by the orbital motion of planets from the apparent RV variations caused by the spectral line-shape variability aroused by stellar activity. This method is effective in reducing the uncertainty arising from the apparent RVs due to stellar variability, and hence enabling the detection of low-mass exoplanets signals in data from active stars.
Here we present results obtained from the application of SCALPELS to the RV data of Sun and an active, exoplanet hosting star. The results show the efficiency of this approach in correcting for confusing stellar activity signals and hence allowing more accurate mass characterisation by improving the fidelity of RV measurements. Overall, this would result in a significant improvement in the community's ability for precise follow-up characterisation of exoplanet systems detected by TESS.
poster number: 1.23 | zenodo
Angelica Psaridi
(Geneva Observatory)
François Bouchy, Geneva Observatory
Monika Lendl, Geneva Observatory
The detection and characterization of exoplanets around a broad range of host stars, including massive A-F stars, is essential to investigate and constrain the impact of stellar mass on planet properties. However, planets around hot massive hosts are still relatively unexplored in radial velocity (RV) surveys because of the small number of stellar lines that are usually broadened and blended by stellar rotation and jitter. As a result, the available information about the formation and evolution of planets around hot stars is limited. Our observing program focuses on bright (V<12) giant (>7 Re) planet and brown dwarf candidates orbiting stars with effective temperatures above 6200 K identified from the TESS mission. For the confirmation of their planetary nature and the determination of their mass and orbital properties, we use RVs and spectra mainly from CORALIE and other instruments as part of the TESS Follow-up Observing Program. For some fast rotating stars that require higher precision and efficiency we foresee to use HARPS. We present our global statistical analysis of TESS candidates transiting early-type stars, the detection of the confirmed brown dwarf TOI-629b, as well as preliminary results obtained on other candidates.
poster number: 2.01 | zenodo
Ankita Waghmare
(Ramniranjan Jhunjhunwala College, Ghatkopar West, Mumbai, India)
Sampada Gaonkar : Ramniranjan Jhunjhunwala College, Ghatkopar West, Mumbai, INDIA.
Jatin Rathod : Nehru Planetarium, Mumbai, India
Ankush Bhaskar :Space Physics Laboratory, VSSC, Trivandrum, India
The habitability of the exoplanet has a strong dependence on the stellar activity of the host star. M-dwarf stars constitute a large fraction of the stellar population, therefore they are of primary interest in searching potentially habitable exoplanets. It is easier to detect planets around low mass stars since they have effectively smaller radii and low temperatures due to which we can easily detect planet transits. The stellar flares from the host star may play a crucial role in triggering prebiotic chemistry on the exoplanet, whereas large frequency flares and CMEs would lead to atmospheric erosion and ozone depletion. The stellar flares sometimes are associated with Coronal Mass Ejections, which may directly impact the exoplanetary atmospheres and affect habitability. Here, we present a case - study of the flaring activity of an M-dwarf star and its impact on its orbiting exoplanet in the habitable zone. We utilized the light-curve data from TESS. We used the AltaiPony python-based package to identify flares. We further analyze and quantify the flare activity to understand its possible impact on the exoplanet environment around the habitable zone.
poster number: 2.02 | zenodo
Antoine Thuillier
(Université de Liège)
V. Van Grootel (1) , F.J. Pozuelos (1) , M. Dévora-Pajares (2) , S. Charpinet (3)
1 : STAR Institute, Université de Liège
2 : Dpto. Fı́sica Teórica y del Cosmos. Universidad de Granada
3 : IRAP, Universite de Toulouse
In this presentation I will give an insight of my PhD project dedicated to the search for exoplanets around hot subdwarf stars (sdO/B). I use data from the missions Kepler, K2, TESS and CHEOPS, in order to detect transits of close bodies down to the size of the Earth. This is possible thanks to the small size of this type of star, as we confirmed by performing injection-and-recovery tests (details on which sizes and orbits we can reach given existing data will be given during the talk). Such bodies are key to understand the fate of close orbiting exoplanets that have been through an engulfment during the Red-Giant-Branch (RGB) phase of their host. But so far no exoplanets have been confirmed around sdO/B and their actual fate still have to be addressed with observational evidence. My project is therefore to perform a transit survey in all available light curves of hot subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS) in order to compute meaningful statistics regarding planetary occurrences of sub-stellar bodies around hot subdwarfs. Moreover this will provide strong constraints for the survival of exoplanets that endured an engulfment phase, when their host expanded.
poster number: 2.03 | zenodo
Archit Kalra
(Carmel High School)
Although some reactions such as the synthesis of water and carbon dioxide are spontaneous on Earth, there are a large number of exoplanets with atmospheres in which these reactions are nonspontaneous, indicating that they may not normally exist in the atmospheric composition of the exoplanet. Inversely, some reactions such as the synthesis of nitrogen dioxide are nonspontaneous on Earth, but may be spontaneous on an exoplanet. Here I use basic equilibrium chemistry to describe some attributes of possible exoplanets in which carbon dioxide synthesis is nonspontaneous, in which case carbon may exist as graphite, as well as in an exoplanet with spontaneous nitrogen dioxide synthesis, in which case important atmospheric processes may differ depending on how nitrogen interacts with other species present in the exoplanetary atmosphere. I cross-reference the average temperatures at which the reactions would have a standard Gibbs Free Energy of formation of 0 kJ/mol with the available equilibrium temperature data for discovered exoplanets and identify possible locations where the discussed reactions may be spontaneous or nonspontaneous.
poster number: 2.04 | zenodo
Armen Tokadjian
(USC/Carnegie Observatories)
Anthony Piro - Carnegie Observatories
Exomoons may play an important role in determining the habitability of worlds outside of our solar system. They can stabilize conditions, alter the climate by breaking tidal locking with the parent star, drive tidal heating, and perhaps even host life themselves. However, the ability of an exoplanet to sustain an exomoon depends on complex tidal interactions. Motivated by this, we make use of simplified tidal lag models to follow the evolution of the separations and orbital and rotational periods in planet, star, and moon systems. We apply these models to known exoplanet systems to assess the potential for these exoplanets to host exomoons. We find that there are at least 36 systems in which an exoplanet in the habitable zone may host an exomoon for longer than one gigayear. This includes Kepler-1625b which we determine would be able to retain a Neptune-sized moon for longer than a Hubble time. These results may help provide potential targets for future observation. In many cases, there remains considerable uncertainty in the composition of specific exoplanets. We show the detection (or not) of an exomoon would provide an important constraint on the planet structure due to differences in their tidal response.
poster number: 2.05 | zenodo
Arvind Gupta
(Pennsylvania State University)
The exoplanet yield of the TESS mission is expected to surpass that of Kepler, and the relatively bright stars observed by TESS will be significantly more amenable to RV follow-up. Yet TESS is more sensitive to detection biases than its predecessor, as close to 75% of the sky coverage of the TESS primary mission has a continuous time baseline of just 27 days. In these regions of the sky, TESS will observe no more than a single transit for any exoplanet with an orbital period longer than a month. The orbital parameters that can be derived for these “single-transit planet candidates” (STPCs) will be poorly constrained relative to those derived for exoplanets observed to transit multiple times, posing a challenge for follow-up observations. But long-period planets are nevertheless worth confirming and characterizing. Here, I present a framework for maximizing the efficiency of RV observations of STPCs. By leveraging information on exoplanet populations from Kepler, I show that one can develop an informed follow-up strategy even without strong constraints on the orbital period or eccentricity. I also highlight how this information can be used to design dynamic, adaptive observing schemes for queue-based instruments such as NEID.
poster number: 2.06 | zenodo
Avi Shporer
(MIT)
Karen Collins, Harvard Smithsonian CfA
Marshall Johnson, LCO
James Armstrong, University of Hawaii
Tim Brown, LCO
Dennis Conti, AAVSO
Ben Fulton, IPAC
Tianjun Gan, Tsinghua University
Keith Horne, University of St. Andrews
Eric Jensen, Swarthmore College
Daniel Jontof-Hutter, University of the Pacific
John Kielkopf, University of Louisville
Dave Latham, Harvard Smithsonian CfA
Shude Mao, Tsinghua University
Bob Massey, Villa ‘39 Observatory
Tsevi Mazeh, Tel Aviv University
Felipe Murgas, IAC
Norio Narita, National Astronomical Observatory of Japan
Enric Palle, IAC
Markus Rabus, Universidad Católica de la Santísima Concepción
Richard Schwarz, Patashnick Voorheesville Observatory
Ramatholo Sefako, SAAO
Sahar Shahaf, Tel Aviv University
Rob Siverd, Gemini Observatory
Gregor Srdoc, Kotizarovci Observatory
Chris Stockdale, Hazelwood Observatory
Accomplishing the exoplanet science enabled by TESS requires follow-up of many transiting planet candidates throughout the entire sky, to identify false positives (FPs) and confirm real planets. An efficient follow-up requires a global facility and a large amount of telescope time. This Las Cumbres Observatory (LCO) Key Project is designed to do just that, with about 2,500 hours of telescope time per semester for 6 semesters, 2020B - 2023A. LCO telescopes are fully automated, including 10 x 0.4m, 11 x 1.0m, and 2 x 2.0m telescopes in 7 sites. We are using all LCO telescopes, equipped with imagers, and we also have time on the high resolution NRES spectrographs, installed in 4 sites. Imagers are used to observe the TESS candidates during transit and check if the transit signal seen in TESS data originates from the target or from a nearby star blended with the target in the TESS wide pixels and wide PSF. The NRES spectrographs are used for measuring the stellar parameters of bright TESS candidate host stars down to 10th magnitude, identifying obvious FPs (SB1, SB2), and measuring the orbits of massive planets. This Key Project is part of most TESS planet discoveries. We present our methodologies and some of our discoveries.
poster number: 2.07 | zenodo
Aviad Panahi
(Tel Aviv University)
Tsevi Mazeh, Tel Aviv University
Shay Zucker, Tel Aviv University
Starting in 2021, ESA's Gaia mission shares with TESS information about unpublished Gaia photometry of TOIs and their nearby stars, taking advantage of Gaia's much higher angular resolution to identify false positives due to nearby eclipsing binaries and in many cases to confirm that the transits detected by TESS are on the announced host star. The performance of the identification depends mainly on the number of Gaia data points included in the transit and their precision. In the recent TESS batches we were able to confirm more than 5% of the TESS candidates and refute another 5% as false positive candidates. We present our performance as a function of the period of the planet candidate and the TESS derived depth. We also discovered two planet candidates residing in wide binaries. We anticipate the process to be more productive when more Gaia measurements are available in the near future.
poster number: 2.09 | zenodo
Bob Aloisi
(University of Wisconsin - Madison)
Robert Aloisi (UW - Madison), Andrew Vanderburg (UW - Madison), Patrick Selep (UW - Milwaukee), Adam Popowicz (Faculty of Electronics, Electrical Engineering and Microelectronics, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland)
Krzysztof Bernacki (Faculty of Electronics, Electrical Engineering and Microelectronics, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland), Josch Hambsch (Vereniging Voor Sterrenkunde (VVS), Oostmeers 122 C, 8000 Brugge, Belgium), Tom Kaye (Citizen Scientist), Arto Oksanen (Citizen Scientist), Barbara Harris (Citizen Scientist) , Saul Rappaport (MIT Kavil Institute for Astrophysics and Space Research)
We are leading a project to identify candidate exoplanets transiting white dwarf (WD) stars by searching TESS Full Frame Images (FFI) at locations of GAIA DR2 WD stars with magnitudes less than 18.0. This effort complements approved high cadence (2 minute or 30 second) observations of selected WD stars using TESS. Typical magnitudes for white dwarf stars with TESS candidate transits are from V 15.0 to 18.0. Typical candidate exoplanet periods may be 30 minutes to 4 days with transits lasting from 2 to 30 minutes. A Python code utilizing LightKurve and box fitting linear least square (BLS) periodograms is being developed to identify promising candidates. Ground-based follow-up with modest size (12” to 20” aperture) telescopes is possible because WD transits are relatively deep. Observations are being completed by an international collaboration. To date, we have found short period (~3 hour), short duration (~20 minutes) transits of small red dwarf stars and even shorter period (40 minutes) sinusoidal signals likely caused by star spots. Future work will include searching TESS FFI at locations of white dwarf stars identified in GAIA EDR3.
poster number: 2.10 | zenodo
Brett Addison
(University of Southern Queensland)
Emil Knudstrup (Aarhus University)
Ian Wong (MIT)
Guillaume Hebrard (Universite Pierre \& Marie Curie)
Patrick Dorval (Leiden University)
Ignas Snellen (Leiden University)
Simon Albrecht (Aarhus University)
Aaron Bello-Arufe (Technical University of Denmark)
Jose-Manuel Almenara (Universit\'e Grenoble Alpes)
Isabelle Boisse (Aix Marseille Univ)
Xavier Bonfils (Universit\'e Grenoble Alpes)
+ 62 additional co-authors
Here I present the discovery of an ultra-hot Jupiter, TOI-1431b/MASCARA-5b, detected by TESS and MASCARA. Radial velocity measurements with SONG, SOPHIE, FIES, NRES, and EXPRES confirms the planet candidate with a reflex motion of K=294.1±1.1m/s. A joint analysis of the photometry and RVs gives TOI-1431b a mass of Mp=3.14±0.19MJ, an inflated radius of Rp=1.51±0.06RJ (16.9±0.7Re), and an orbital period of P~2.65d. The planet orbits a bright (V=8.05mag), young (~290Myr), and hot (Teff~7700K) Am type star. Using TESS photometry, we were able to measure the planet's thermal emissions in the red-optical from the full phase curve and secondary eclipse, allowing us to determine the dayside and nightside temperature of its atmosphere as Tday=2983±68K and Tnight=2556±65K. The planet's low day/night temperature contrast (~400K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness, the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as JWST and ARIEL.
poster number: 2.11 | zenodo
Brian Jackson
(Boise State University)
Alex Hindle (Newcastle University), Tami Rogers (Newcastle University, Planetary Science Institute), and Elisabeth Adams (Planetary Science Institute)
Exoplanetary phase curves, light reflected and emitted by the planet as it orbits its star, have revealed exotic weather on these distant worlds. For example, blistering temperatures (~2000 K) on the cloudless daysides of ultra-hot Jupiters partially ionize the atmospheres, providing the magnetic field a handhold to sculpt weather. The resulting competition between transport of angular momentum, which can produce an equatorial jet, and magnetic stresses, a source of atmospheric drag, can drive the hottest region in the atmosphere back and forth acros the sub-stellar point. Recent work using phase curves observed by the Kepler mission has shown that the phasing and amplitude of phase curves may therefore directly constrain the strength of an ultra-hot Jupiter’s magnetic field. Detections of ultra-hot Jupiter phase curves within TESS observations promise to expand the scope of magneto-meteorological studies. In this presentation, we explore the possibilities for constraining magnetic fields with observations of ultra-hot Jupiter phase curves from TESS.
poster number: 2.12 | zenodo
Casey Brinkman
(University of Hawai'i Institute for Astronomy)
Lauren Weiss and Daniel Huber, University of Hawai'i Institute for Astronomy
TOI-561 is a galactic thick disk star hosting an ultra-short period planet of 1.45 Earth radii: one of the oldest known Earth-sized exoplanets (∼10 Gyr), and among the first discovered beyond the thin disk of our galaxy. TOI-561 is one of the most iron depleted (-0.41 dex) and alpha abundance enriched (0.23 dex) exoplanet hosts. To determine if this planet inherited the chemical composition of its primordial nebula, we fit geologically motivated equations-of-state for iron and silicate to the mass and radius measurements. However, there are conflicting mass measurements for TOI-561b in the literature. To resolve this tension, we will present the first simultaneous radial velocity program combining Maroon-X, a new precision RV spectrometer on Gemini-N, and HIRES, a well-characterized spectrometer on Keck I. We find that this planet has the lowest RV-measured density for planets between 1-1.5 R⊕ (4.3±0.3 g/cm3). With an equilibrium temperature of 2500 K and a radius typical of rocky planets, we would expect TOI-561b to have a rocky/metallic composition. Instead, the measured density is 3𝜎 lower than the density of a pure silicate planet, suggesting it has a volatile envelope perhaps from magma outgassing or mantle evaporation.
poster number: 2.13 | zenodo
Dan Moldovan
(Google)
Anne Dattilo (UCSC), Chelsea Huang (MIT ⇨ USQ), Michelle Kunimoto (MIT), Avi Shporer (MIT), Evan Tey (MIT), Andrew Vanderburg (University of Wisconsin-Madison)
The TESS mission produced a large amount of time series data, only a small fraction of which contain detectable exoplanetary transit signals. Deep learning techniques such as neural networks proved effective at differentiating promising astrophysical eclipsing candidates from stellar variabilities, and instrument systematics in an efficient, unbiased and sustainable manner. This talk presents a high quality training data set based on observations from the primary TESS mission full frame images, using a thorough process for manual review and labeling. We used this data set to train a neural network derived from the AstroNet architectures developed by Shallue & Vanderburg (2018) and Yu et al. (2019). We show promising performance results on held-out and extended TESS mission data, as well as the TESS Object of Interest catalog. The new model is currently used for Quick Look Pipeline to filter through its detections. We will also present ongoing work on training a new neural network to distinguish planetary transiting signals from eclipsing astrophysical false positives such as on target, nearby and background eclipsing binaries.
poster number: 2.14 | zenodo
Daniel Revilla Martínez de Albéniz
(Universidad Complutense de Madrid)
Revilla, D. (UCM); Skrzypinski, S. L. (UCM); Montes, D. (UCM); Caballero, J. A. (CAB); Béjar, V. J. S. (IAC); Shang, Y. (IAG); Morales-Calderón, M. (CAB); Vanaverbeke, S. (AstroLAB); et al.
We go on paving the way for the study of Earth-like exoplanets around M-type dwarfs stars by measuring the rotation periods of stars observed by the CARMENES survey using TESS data. This will help to distinguish exoplanet radial-velocity signals from the ones produced by features on the rotating surface. We looked for signals in the photometric time series of 352 CARMENES M dwarfs (GTO sample) covered by the first 26 TESS sectors. We collected either SAP (Simple AperturePhotometry) or PDCSAP (Pre-search Data Conditioning SAP) time series for 210 stars, and custom extracted the light curves for a further 32 stars from the FFI (Full Frame Images). We measured 69 rotational periods between 0.1 d and 13.2 d of which 23 are new. With those periods in hand, we studied the distribution of angular momenta of stellar systems with and without planets.
poster number: 2.15 | zenodo
David Armstrong
(University of Warwick)
The NCORES consortium
The mass and density of a planet’s core tells us about the core ice-mass fraction, a direct connection to the formation process. In most cases the gaseous envelope hides this core, meaning we cannot determine its composition. In situations where the planet is exposed to intense radiation, that gaseous envelope may be lost, providing us with a unique opportunity. I will describe current results and motivation for the NCORES program, a HARPS campaign to characterize TESS-discovered planets orbiting close in to their host stars where photoevaporation can play a dominant role. To date NCORES has led or contributed to the mass-determination of 20 TESS planets smaller than 4R_earth, making a significant contribution to the Level 1 science goal. NCORES aims to produce a well-characterized sample of bright TESS planets to enable the study of close-in planets and cores on an individual and population level. I will discuss some key results from the program, including TOI-849, the remnant core of a giant planet, and multi-planet systems such as TOIs-125, 431 and 1233.
poster number: 2.16 | zenodo
David Baker
(Austin College)
Neil Cutting, Lindy Luker, Tanner O’Dwyer, Chloe Schnaible, Brett Skinner (Austin College)
The TESS Follow-Up Observing Program (TFOP) provides an extraordinary opportunity for undergraduates to gain experience in astronomy research. Austin College is a small liberal arts college in Texas with a strong track record of undergraduate scientific research, and the Adams Observatory at Austin College has delivered TFOP Sub-Group 1 (SG1) photometric observations since 2018. However, the global COVID-19 pandemic placed unique challenges on our exoplanet research program, forcing a completely remote experience in 2020 and a hybrid environment in 2021. Here we report results from our 2020-21 TFOP research filled with verified planet candidates, false positives, and rewarding collaborations in the time of COVID.
poster number: 2.17 | zenodo
Dax Feliz`
(Vanderbilt University)
Peter Plavchan (George Mason University), Samantha N. Bianco (Vanderbilt University), Mary Jimenez (George Mason University), Kevin I. Collins (George Mason University) Bryan Villarreal Alvarado (University of Costa Rica) and Keivan G. Stassun (Vanderbilt University)
In this work, we present the analysis of 33,054 M-dwarf stars located < 100 pc in the Transiting Exoplanet Survey Satellite (TESS) Full Frame Images (FFIs) of the observed sectors 1-5. We present a new pipeline called NEMESIS which was developed to extract detrended photometry and perform transit searches of single sector data in TESS FFIs. As many M-dwarfs are faint and are not observed with a 2 minute cadence by TESS, FFI transit surveys can give an empirical validation of how many planets are missed by using the 30 minute cadence data. In this work, we detected 183 threshold crossing events and present 29 planet candidates for sectors 1-5, 24 of which are new detections. Our sample contains orbital periods ranging from 1.25-6.84 d and planetary radii from 1.26-5.31 Earth radii. With the addition of our new planet candidate detections along with previous detections observed in sectors 1-5, we calculate an integrated occurrence rate of 2.49+/-1.58 planets per star for the period range between 1-9 days and planet radius range between 0.5-11 Earth radii. We project an estimated yield of 122+/-11 transit detections of nearby M-dwarfs.
poster number: 2.18 | zenodo
Di-Chang Chen
(Nanjing University)
Professor Ji-Wei Xie, Nanjing University
Professor Ji-Lin Zhou, Nanjing University
Dr. Jia-Yi Yang, Nanjing Univeristy
Professor Subo Dong, Beijing University
Professor Chao Liu, University of Utah
Professor Yang Huang, Yunan University
To data over 4000 exoplanets have been identified and thousands of candidates are to be confirmed, which has spread from solar neighborhood to several kpc. What are the differences between planetary systems in different galactic environments? To address these questions, we conduct a research project, dubbed Planets Across Space and Time (PAST). In the Paper I and II of the PAST series, we revisit the kinematic method for classification of Galactic components and extend the applicable range of velocity ellipsoid from ∼100 pc to ∼1500 pc from the Sun. Furthermore, we revisit the age–velocity dispersion relation (AVR), which allows us to derive kinematic ages with a typical uncertainty of 10–20%. Applying the above revised methods, we present two catalogs of kinematic properties as well as other basic stellar parameters for 2174 host stars of 2872 planets and 35,864 Kepler stars . With the kinematic catalogs, we find that the fraction of thin (thick) disk stars increases (decreases) with the transiting planet multiplicity (Np = 0, 1, 2 and 3+) and the kinematic age decreases with Np, which could be a consequence of the dynamical evolution of planetary architecture with age.
poster number: 2.19 | zenodo
Dolev Bashi
(Tel-Aviv University)
Shay Zucker, Tel-Aviv University
The planetary systems detected so far exhibit a wide diversity of architectures, and various methods have been proposed to quantitatively study this diversity. Straightforward ways to quantify the difference between two systems, and more generally two sets of multi-planetary systems, are helpful for studying this diversity. In this work we present a novel approach, using a weighted extension of the energy distance (WED) metric, to quantify the difference between planetary systems on the logarithmic period-radius plane. By applying exploratory machine-learning tools, we attempt to find whether there is some order that can be ascribed to the set of multi-planet Kepler system architectures. Based on the WED, the ‘Sequencer’, which is such an automatic tool, identifies a progression from small and compact planetary systems to systems with distant giant planets. Next, we extend the WED to define the inter-catalogue energy distance – a distance metric between sets of multi-planetary systems. We suggest using these metrics as complementary tools in attempts to compare different architectures of planetary systems and, in general, different catalogues of planetary systems.
poster number: 2.20 | zenodo
Drake Lehmann
(University of Wisconsin - Madison)
Andrew Vanderburg (University of Wisconsin - Madison)
There are many planet candidates identified by the Kepler space telescope that have yet to be confirmed or denied as false positives. We are investigating these planet candidates by combining data from both Kepler and TESS. In particular, we are searching for false positives using ephemeris matching between the two datasets. Ephemeris matching works by comparing periodicities found in the light curves from two unrelated stars that are close to each other. From this, we can deduce the orbital period of the potential exoplanet. If the light curves both show the same period, it is likely a false positive. Ephemeris matching allows us to identify false positives caused by background contamination caused by astrophysical events like eclipsing binary stars, and detector artifacts like charge transfer inefficiency and electronic crosstalk. On its own, the Kepler dataset is highly sensitive, but only includes certain pre-selected stars, while TESS returns data from the entire field of view, but with lower precision. By combining the data sets, we are able to confirm or rule out more planets than either would by itself. Our goal is to remove false positives from the sample of possible planets and boost confidence in the surviving signals.
poster number: 2.21 | zenodo
Edward Bryant
(University of Warwick)
Daniel Bayliss (University of Warwick)
Determining the occurrence rate of giant planets orbiting low mass stars (M<0.6Msun) is a critical test of the core-accretion theory of planet formation. However the occurrence rate these giant planets is poorly constrained from previous surveys. In this study we determine this occurrence rate using the hundreds of thousands of low-mass stars monitored in the TESS FFIs.
We perform an automated transit search through light curves extracted from the TESS full frame images for low-mass dwarf stars selected using TIC parameters. Candidates are selected by a series of objective vetting steps that identify and reject false positive cases, particularly eclipsing binary systems and variable stars. Injection and recovery tests are used to to determine our survey efficiency, which in turn allows us to determine the frequency of giant planets around low mass stars in a statistically robust manner. We will present our key findings and discuss how our results impact on the understanding of how giant planets form around their host stars.
poster number: 2.22 | zenodo
Elisa Goffo
(Dipartimento di Fisica, Università degli Studi di Torino)
Davide Gandolfi, Dipartimento di Fisica, Università degli Studi di Torino
Artie P. Hatzes, Thüringer Landessternwarte Tautenburg
KESPRINT Consortium
To understand the formation and evolution of small terrestrial planets not only their internal structure but also the architecture of their host system must be known. Systems harboring long-period cold gas giants tend to host close-in small planets. The presence of outer companions seems to influence the formation and evolution of super-Earths. Unfortunately, our knowledge is still incomplete. Currently, the sample size for these systems is small and the relevant parameters are unknown. Radial velocity follow-up observations of planetary systems hosting close-in small transiting planets can probe the outer architecture of their host system.
I will here present the results of an ongoing radial velocity follow-up program conducted with the HARPS spectrograph, which aims at measuring the masses of transiting planets discovered by the TESS space telescope. The 4-year baseline of our HARPS program is allowing us to search for long-period planets, expanding the horizon and probing the the outer architecture of planetary systems with inner small planets.
poster number: 2.23 | zenodo
Elyse Incha
(UW-Madison)
David Latham, CfA
Allyson Bieryla, CfA
Steve Howell, NASA Ames
Andrew Mann, UNC
Tom Jacobs, Citizen Scientist
Daryll Lacourse, Citizen Scientist
Andrew Vanderburg, UW-Madison
At the end of the K2 mission, just before it ran out of fuel, Campaign 19 was conducted but cut short which resulted in an extremely short set of observations. The small amount of data recorded makes discovering exoplanets within the Campaign 19 dataset difficult. To our knowledge, no other teams have been able to find exoplanets in the Campaign 19 dataset yet. We are using this dataset to search for single transits and characterize new planetary systems. Despite the short duration of the dataset provided from K2, we are still able to determine important characteristics of the star and planet, such as radius, mass, period, and the likelihood of the planet residing in the habitable zone. We are complementing the K2 data with observations from ground-based telescopes. Our work will help ensure that all K2 data is utilized to its full potential so that no planets are left behind. These techniques can be adapted and applied to single transit systems recorded by other telescopes such as TESS.
poster number: 2.24 | zenodo
Emilie R. Simpson
(University of California, Riverside)
Stephen Kane (University of California, Riverside), Tara Fetherolf (University of California, Riverside), Joshua Pepper (Lehigh University), Teo Mocnik (Gemini Observatory)
Characterizing an exoplanet requires knowledge of its host star’s intrinsic properties. The activity of a star can lend a unique perspective of how the star interacts with an exoplanet atmosphere and the ability to confirm an exoplanet’s place in a system. We will discuss how variable behavior in known exoplanet host stars can be responsible for the discovery of possible false positive signatures. The main points of this work include an overview of how the stellar photometry were processed for ~650 known exoplanet hosts observed by TESS, and the methodology of identifying strong stellar variability. We include a discussion on how this analysis can be applied to both current and future catalogs to search for false positives in an effort to reduce the false positive rate in confirmed planet catalogs. We identify specific cases for which the period of variability closely matches the known planet orbital period, and thus may be indicative of a false positive exoplanet signature.
poster number: 3.01 | zenodo
Emma Turtelboom
(UC Berkeley)
Lauren Weiss (University of Hawaii), Courtney Dressing (UC Berkeley), Grzegorz Nowack (IAC), Enric Palle (IAC), TESS-Keck Survey (TKS) collaboration, KESPRINT collaboration
TOI 1246 is one of only eight four-planet systems with measured masses and radii for all four planets. We have collected radial velocity follow-up observations with Keck/HIRES and TNG/HARPS-N and have measured all four planet masses to greater than 3 sigma precision. In both the inner and outer pair of planets, while the planets’ radii are similar, they have surprisingly diverse masses (5.4-17.6 Me across the system). We confirm the four transiting sub-Neptunes around this moderately bright K dwarf (V=11.6, K=9.9). We refit the 12 sectors of TESS photometry to refine planet radius estimates and search for evidence of transit timing variations. The outer two planets, TOIs 1246.01 (P=18.7d, R=3.42±0.10Re, M=8.2±2.8Me) and 1246.04 (37.9d, R=3.61±0.10Re, M=17.6±3.4Me) lie just exterior to the 2:1 resonance, and demonstrate transits inconsistent with a linear ephemeris. The inner two planets (1246.02: P=4.1d, R=2.47±0.10Re, M=5.4±1.7Me and 1246.03: P=5.9d, R=2.37±0.10Re, M=9.7±1.8Me) are tightly packed. This system is brighter than most other multi-planet systems, and is a particularly interesting testing ground for mass loss and formation hypotheses due to the high planet multiplicity and varied planet masses.
poster number: 3.03 | zenodo
Evan Tey
(MIT)
Chelsea Huang (MIT ⇨ USQ), Michelle Kunimoto (MIT)
Multiplanet systems are rich environments for comparison studies of exoplanets. Kepler found an abundance of these systems, putting TESS in a good position to discover more. In particular, TESS should find 100s of multiplanet systems (Huang et al. 2018) around brighter stars, making it easier to characterize them with mass measurements or atmospheric spectroscopy. So far, though, systematic multiplanet searches have only been conducted with the SPOC pipeline on the short cadence light curves. In this talk, I present results from the first systematic search for multiplanet systems using TESS Full-Frame Images -- broadening the search for multiplanet systems to 150,000 bright main sequence stars. I use Threshold-Crossing Events from the Quick Look Pipeline (QLP) as starting points for a search of multiplanet systems around main sequence stars with Tmag < 12.5. I show results from Years 1 through 3 and have also integrated the code into QLP for Year 4+. I’ll discuss newly discovered systems in context of existing multiplanet system statistics and suggest interesting systems for follow-up. Together with known systems, these new multiplanet systems will improve our understanding of planetary system formation and evolution.
poster number: 3.04 | zenodo
Fan Yang
(Beijing Normal University, China; National Astronomical Observatory, Chinese Academy of Science)
Ranga-Ram Chary (Caltech, IPAC)
We re-analyze transit depths of KELT-19Ab, WASP-156b, WASP-121b, and WASP-161b including data from TESS. We propose an iterative method using an empirical Bayesian approach for modeling the limb darkening parameters for WASP-121b. Comparing to the discovery work, we find the first three sources have a larger inclination when using 2-minute data. Simulations show that undersampling (i.e. > 5 minutes) results in a smaller inclination, and biased Rp/R*. Current re-sampling methods could correct for the inclination bias but not the Rp/R*. We constrain the inclination to previous work and find Rp/R* for KELT-19Ab from TESS data is 3.5\sigma smaller than previous work, but consistent to within ~ 2\sigma for WASP-156b and WASP-121b. The result for KELT-19Ab suggests a haze-dominant atmosphere. We also find WASP-161b has a larger Rp/R* at the 2\sigma level from TESS and previous data. We have approved CHEOPS observations of WASP-161b for correcting the influence of sampling rate distortions of the light curve, and errors in the derived limb darkening parameters. The accurate determination of these parameters will then be used as priors in the re-analysis of the previous light curves for a joint recharacterization of its atmosphere.
poster number: 3.05 | zenodo
Gabriel de Oliveira Gomes
(Institute of Astronomy, Geophysics and Atmospherical Sciences (IAG/USP))
Emeline Bolmont (Observatoire de Genève) , Sergi Blanco-Cuaresma (Harvard-Smithsonian Center for Astrophysics)
In this work, we investigate the influence of planetary tidal interactions on the transit-timing variations of short-period low-mass rocky exoplanets. For this purpose, we employed the recently developed creep tide theory to compute tidally induced TTVs. As a working example for the analyses of tidally induced TTVs, we study the K2-265 b planet. We analyzed the dependence of tidally induced TTVs with the planetary rotation, uniform viscosity coefficient and eccentricity. Our results show that the tidally induced TTVs are more significant in the case where the planet is trapped in nonsynchronous spin-orbit resonances, in particular the 3/2 and 2/1 spin-orbit resonant states. An analysis of the TTVs induced separately by apsidal precession and tidally induced orbital decay has allowed for the conclusion that the latter effect is much more efficient at causing high-amplitude TTVs than the former effect by 2 - 3 orders of magnitude.
poster number: 3.06 | zenodo
Gaia Lacedelli
(University of Padova)
Well-characterized multiplanetary systems offer a unique opportunity for comparative planetology, allowing for investigations of the formation and evolution processes. I will present the analysis of a new multiplanetary system, TOI-561, initially discovered by the TESS mission through photometric observations, and further characterized using high-precision RV data collected with the HARPS-N spectrograph, that allowed us to obtain precise masses for all the four planets in the system, namely an ultra-short period super-Earth and three mini-Neptunes (Lacedelli et al. 2020). I will show how in this case combining photometric and RV data has been essential to discriminate between various possible architectures, highlighting the importance of combining different techniques to obtain a better characterization of a planetary system. Additional insights on the planetary architecture and internal structure are coming from the ultra-high precision photometry of the CHEOPS satellite, which additionally stresses the importance of synergies between various techniques and instruments.
poster number: 3.07 | zenodo
Galen Bergsten
(Department of Planetary Science & Lunar and Planetary Laboratory, The University of Arizona)
Ilaria Pascucci + Lunar and Planetary Laboratory, The University of Arizona
Gijs Mulders + Universidad Adolfo Ibanez
The “radius valley” is a feature in the short-period, small exoplanet population in Kepler and K2 data showing an abundance of super-Earths and mini-Neptunes, with a relatively scarce population of intermediate-sized planets between the two. Several studies explore the radius valley’s dependence on host star properties, specifically stellar age and mass, with a wide range of treatments to the population of small close-in planets. We employ updated stellar properties and implement refined measures of completeness and reliability to observe how the Kepler small planet population varies as a function of stellar mass. These results are extrapolated into the Habitable Zone, placing an estimate on the occurrence rate of habitable, Earth-like planets that still retain their atmospheres. We further attempt to constrain the degree of stripped cores “contaminating” the super-Earth population as a function of period, which will help constrain models of photoevaporation and core powered mass loss. We discuss these results in the context of TESS and compare preliminary demographics between the Kepler field and the solar neighborhood.
poster number: 3.08 | zenodo
Georgina Dransfield
(University of Birmingham)
Georgina Dransfield - University of Birmingham; Amaury HMJ Triaud - University of Birmingham; Tristan Guillot - Universite ́ Côte d’Azur; Lyu Abe - Universite ́ Côte d’Azur; Djamel Mekarnia - Universite ́ Côte d’Azur; Nicolas Crouzet – European Space Agency; Francois-Xavier Schmider - Universite ́ Côte d’Azur; Karim Agabi - Universite ́ Côte d’Azur; Olga Suarez - Universite ́ Côte d’Azur;
Of the 870+ southern planetary candidates from TESS currently awaiting confirmation, roughly 10% have transit durations longer than five hours; over a third of these also have orbital periods longer than 20 days. Systems like these could fall into the sparsely populated parameter space of long-period gas giants; but long transits that happen infrequently present an observational challenge from the ground. Not so for ASTEP, a 40cm telescope installed at Dome C in Antarctica. ASTEP’s proximity to the South Pole means that it enjoys outstanding photometric conditions, as well exceptional phase coverage due to uninterrupted observing during the Austral Winter. In this talk I will share some results from ASTEP’s first seasons of SG1 observing, including uninterrupted 10 hour-long transits, TTV monitoring, and the first ever ground-based transit of a circumbinary planet. I will also show that ASTEP has the potential to make a significant contribution to ephemeris refinement for upcoming missions such as JWST and Ariel.
poster number: 3.09 | zenodo
Giacomo Mantovan
(Università degli studi di Padova)
Marco Montalto (Università degli studi di Padova)
Giampaolo Piotto (Università degli studi di Padova)
Seeing-limited on-off photometry is an efficient follow-up technique which permits to identify false positives among transiting planetary candidates produced by space missions like TESS. Here we present our own on-going follow-up program of TESS candidates orbiting G-type stars. Using Gaia photometry and astrometry we built an absolute color-magnitude diagram and isolated G-type candidates' hosts. Then we performed a probabilistic validation of each candidate using the VESPA software and produced a prioritized list of objects having the highest probability of being genuine transiting planets. By following this procedure we eliminated the majority of false positive candidates. For the remaining set, we are performing on-off photometry to further cull the list of candidates and prepare for the subsequent radial velocity follow-up.
poster number: 3.11 | zenodo
Heather Johnston
(University of Leeds)
Dr Olja Panic - University of Leeds; Dr Beibei Liu - Zhejiang University
Context: Planetary and stellar formation are inherently linked: the physical and chemical compositions of stellar birth environments – the natal protoplanetary disks – are responsible for the resultant planetary conditions. Aims: To examine how stellar hosts and their surrounding protoplanetary disks affect the formation and migration of planets. Methodology: Adapting and utilising the code developed in Liu et al. (2019), and expanding on the findings to include host stars in the range of 1-3M☉and investigate the impact that different conditions – e.g. disk size, accretion rate, and migration – have on planetary growth. Results: There is a clear correlation between giant planet growth and planetary migration. Gas accretion of the protoplanet is more challenging when the mass of the host star is increased. Conclusions & Future Work: The simulations will be compares to current observational findings around solar/intermediate-mass stars and develop some analysis to quantify an observational marker to determine whether a planet formed in situ or experienced type I/II migration.
poster number: 3.12 | zenodo
Hugh Osborn
(MIT)
We report the discovery of HD 110113 b (TOI-755.01), a transiting mini-Neptune exoplanet on a 2.5-day orbit around the solar-analogue HD 110113. Using TESS photometry and HARPS radial velocities gathered by the NCORES program, we find HD 110113 b has a radius of 2.05±0.12 R⊕ and a mass of 4.55±0.62 M⊕. The resulting density of 2.90+0.75−0.59 g/cm^3 is significantly lower than would be expected from a pure-rock world; therefore, HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold onto a substantial (0.1-1\%) H-He atmosphere over its ∼4 Gyr lifetime. Through a novel simultaneous gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8±1.2 d from the RVs and confirm an additional non-transiting planet with a mass of 10.5±1.2 M⊕ and a period of 6.744+0.008−0.009 d.
poster number: 3.13 | zenodo
Ian Wong
(MIT)
Avi Shporer (MIT), Daniel Kitzmann (University of Bern), Kevin Heng (University of Bern), Tara Fetherolf (UC Riverside), Tansu Daylan (MIT), Björn Benneke (Université de Montréal)
The continuous, long-baseline photometry provided by TESS has enabled detailed phase curve studies of planetary systems. Over the course of the two-year Primary Mission, we carried out a systematic light curve analysis of both known targets and newly discovered systems. By measuring the phase curve, we probed fundamental physical quantities, such as the planet’s dayside temperature, Bond albedo, and day-night heat recirculation efficiency, as well as the host star’s response to the mutual star-planet gravitational interaction. In this talk, I provide an overview of the main results from the Primary Mission. We detected phase curves for over 20 targets and combined TESS-band eclipse measurements with Spitzer secondary eclipse depths to obtain self-consistent dayside brightness temperatures and optical geometric albedos. These albedo measurements have revealed an intriguing apparent trend between increasing dayside temperature and increasing geometric albedo for hot Jupiters. With TESS now well into its Extended Mission, we consider possible avenues for follow-up intensive atmospheric characterization and discuss fruitful opportunities for future study as the telescope revisits these systems in the coming years.
poster number: 3.14 | zenodo
Irina N Kitiashvili
(NASA Ames Research Center)
Alan A Wray, NASA Ames Research Center
Detection of Earth-mass planets requires extreme precision radial velocity measurements. However, to capture tiny disturbances due to a planet it is necessary to understand and characterize the host star’s turbulent dynamics to apply the proper filtering to observational data. We take advantage of current computational and technological capabilities to develop 3D realistic models of stellar subsurface convection and atmospheres to estimate the photospheric jitter. We present 3D radiative hydrodynamics models of several solar-type target stars plus initial results of MHD models, comparison with available observations, and preliminary estimates of the stellar jitter for solar-type stars in low-activity states.
poster number: 3.15 | zenodo
Ismael Mireles
(University of New Mexico)
Katharine Hesse (MIT), Natalia Guerrero (MIT), Michelle Kunimoto (MIT), Chelsea Huang (MIT), William Fong (MIT)
After three years of observations, the TESS mission has led to over 2600 TESS Objects of Interest (TOIs) being alerted. Of these, 168 TOIs were alerted because they were first identified as Community TOIS (CTOIs). The sample of promoted CTOIs includes full frame image (FFI) targets that are fainter than the Tmag = 10.5 cutoff used by QLP vetting and single transits that were rejected by the periodic signal searches from the QLP and SPOC pipelines. Here we detail the process by which these CTOIs were promoted to TOIs and present examples that highlight how the community has supplemented the standard TESS pipelines. The inclusion of these community targets will help explore longer-period planets as well as fainter targets that would have otherwise not been alerted as TOIs.
poster number: 3.16 | zenodo
Jake Clark
(University of Southern Queensland)
Natalie Hinkel, Southwest Research Institute
Rob Wittenmyer, University of Southern Queensland
Jonti Horner, University of Southern Queensland
Duncan Wright, University of Southern Queensland
Brad Carter, University of Southern Queensland
Cayman Unterborn, Southwest Research Institute
Mathieu Clerte, University of Southern Queensland
GALAH Collaboration
The time of large-scale astronomical surveys is now upon us. These huge spectral, astrometric and photometric surveys are providing us astronomers with the richest datasets to date, to better characterise the stars contained within the Milky Way like never before. With almost every star being orbited by at least one exoplanet across our galaxy, these large scale surveys can help better inform us in characterising confirmed and potential planet-hosting stars. We've been able to utilise GALAH's last two data releases (DR2 and DR3), along with GAIA DR2 and EDR3 to better characterise over 125 exoplanet hosts and 250 candidate hosting stars, as well as 45,000 stars currently being observed by TESS. This poster also shows how GALAH's chemical abundances can help inform exoplanetary scientists on what types of planets TESS will likely uncover, and some trends in planetary populations with different chemical abundances.
poster number: 3.18 | zenodo
Jan Subjak
(Czech Academy of Sciences)
Nicolas Lodieu, Instituto de Astrofísica de Canarias (IAC)
Petr Kabath, Czech Academy of Sciences
Stars with wide brown dwarf companions that host exoplanets are extremely rare, as only four were reported to date. Different theories propose that planets can be significantly affected by wide BD companions through various processes. They can cause additional peculiarities observed in parameter distributions. Thus, these systems contain great potential and opportunities to enrich our knowledge about the large scale of substellar objects and test our concepts of planetary formation and evolution. However, the sample size is still too small to discuss even the most fundamental questions: What is the fraction of such systems? Are they common, or is there any process that disfavors this scenario? I will present the results of the extensive follow-up program with SONG spectrograph with the additional support of Carmenes spectrograph, in which we are looking for planets in systems with wide brown dwarf companions. The 2-year baseline of observations allows us to discuss even long signals, and the TESS photometry enables us to discard potential stellar activity and measure rotation periods. I will show that these systems are exciting physical laboratories and shed more light on the whole population.
poster number: 3.20 | zenodo
Jiayin Dong
(Penn State)
Chelsea Huang (University of Southern Queensland), Bekki Dawson (Penn State), George Zhou (University of Southern Queensland), Daniel Foreman-Mackey (Flatiron Institute), Karen Collins (CfA), Sam Quinn (CfA), Amaury Triaud (University of Birmingham), Songhu Wang (Indiana), Jack Lissauer (NASA Ames), Thomas Beatty (Arizona), Billy Quarles (Georgia Tech), Lizhou Sha (Wisconsin), Avi Shporer (MIT), Zhao Guo (Cambridge), Stephen Kane (UC Riverside), Lyu Abe (Observatoire de la Cote d'Azur), Khalid Barkaoui (Université de Liège), Zouhair Benkhaldoun (Cadi Ayyad University), Rafael Brahm (UAI), François Bouchy (Geneva), Theron Carmichael (Harvard), Kevin Collins (George Mason University), Dennis Conti (American Association of Variable Star Observers), Nicolas Crouzet (ESA), Georgina Dransfield (University of Birmingham), Phil Evans (El Sauce Observatory), Tianjun Gan (Tsinghua), Mourad Ghachoui (Cadi Ayyad University), Michaël Gillon (Université de Liège), Nolan Grieves (Geneva), Tristan Guillot (Observatoire de la Côte d'Azur), Coel Hellier (Keele University), Emmanuël Jehin (Université de Liège), Eric Jensen (Swarthmore), Andres Jordán (Universidad Adolfo Ibáñez), Jacob Kamler (John F. Kennedy High School), John Kielkopf (University of Louisville), Djamel Mékarnia (Observatoire de la Côte d'Azur), Louise Nielsen (Geneva), Francisco Pozuelos (Université de Liège), Don Radford (Brierfield Observatory), François-Xavier Schmider (Observatoire de la Côte d'Azur), Richard Schwarz (Patashnick Voorheesville Observatory), Chris Stockdale (Hazelwood Observatory), Thiam-Guan Tan (Perth), Mathilde Timmermans (Université de Liège), Gavin Wang (Stanford Online High School), George Ricker (MIT), Roland Vanderspek (MIT), David Latham (CfA), Sara Seager (MIT), Joshua Winn (Princeton), Jon Jenkins (NASA Ames), Ismael Mireles (University of New Mexico), Daniel Yahalomi (Columbia), Edward Morgan (MIT), Michael Vezie (MIT), Elisa Quintana (NASA Goddard), Mark Rose (NASA Ames), Jeffrey Smith (SETI Institute), Bernie Svhiao (MAST)
Warm Jupiters (WJs) – defined here as planets larger than 6 Earth radii with orbital periods 8–200 days – are a key missing piece of our planet formation and evolution theory. It is currently debated whether WJs form in situ or undergo disk or high eccentricity tidal migration. These different classes of origin channels lead to different expectations for WJs’ properties, such as the eccentricity distribution, occurrence rates, and companion properties. I will first introduce a catalog of WJ candidates from a systematic search in the Y1 TESS Full-Frame Images. In collaboration with the TFOP, we validate the catalog using ground-based facilities. I will then show the eccentricity distribution and occurrence rates of the catalog. The eccentricity distribution can be described by a two-population mixture model: a low-e population supporting the in situ or disk migration origins and a high-e population supporting the tidal migration origin. I will highlight the confirmation of TIC-464300749b, an 18-day WJ on a highly elliptical orbit (e~0.8). A few WJs are found with nearby companions. I will lastly discuss the implications of such systems by presenting planetary embryo simulations with WJs formed in situ versus via disk migration.
poster number: 3.21 | zenodo
John Ahlers
(NASA/GSFC & USRA)
Knicole Colon (NASA/GSFC)
Elisa Quintana (NASA/GSFC)
Keivan Stassun (Vanderbilt University)
The angle between the stellar spin angular momentum and the planetary orbital angular momentum --- spin-orbit angle --- is one of the key parameters in understanding a planetary system's architecture and formation history. Traditionally, only a projected (or line of sight) version of this angle can be feasibly measured. A planet's true 3-D spin-orbit angle is more difficult to constrain; as such, only a handful of true spin-orbit angles have been determined to date. Our ongoing research will significantly expand spin-orbit angle demographics by measuring true spin-orbit angles of hot Jupiters orbiting A/F-type stars observed by TESS, where spin-orbit misalignment is most common. We are measuring true spin-orbit angles using the gravity-darkening transit analysis technique, which applies specifically to high-mass, rapidly rotating stars. With precision photometry from TESS, we have for the first time the opportunity to obtain true spin-orbit angles en masse in a straightforward and cost-effective way. Our research will improve accessibility to studying planets transiting A/F stars, a subset that encompasses up to 40% of expected TESS planet discoveries.
poster number: 3.22 | zenodo
Jon F. Otegi
(University of Geneva & University of Zurich)
Jon F. Otegi (University of Zurich & University of Geneva), Francois Bouchy (University of Geneva) and Ravit Helled (University of Zurich)
Previous studies using Kepler data suggest that planets orbiting the same star tend to have similar sizes. Due to the faintness of the stars targeted by Kepler only a small fraction could be detected also via radial velocity, and therefore it is unclear whether these planets are also similar in mass. Follow up programs of TESS targets have lead to a rapid increase number of confirmed planets with mass measurements, allowing for a more detailed statistical analysis of multi-planetary systems. In this work we explore whether planetary systems indeed behave as "peas in a pod" and compare their radii, masses, and period ratios. We show that plantes in the same system that are similar in radii could be rather different in mass and vice versa. Nevertheless, planets are somewhat similar in mass up to masses of ~40Me although the mass measurements are typically less accurate than the radii. We conclude that the peas in the pod pattern is not always valid when considering both the planetary mass and radius. We conclude that measuring the planetary mass accurately and increasing the number of detected systems is critical for understanding the diversity of planetary systems.
poster number: 3.23 | zenodo
Jon M. Jenkins
(NASA Ames Research Center)
Jon M. Jenkins, NASA Ames Research Center
Joseph D. Twicken, SETI Institute/NASA Ames Research Center
Douglas Caldwell, SETI Institute/NASA Ames Research Center
Eric Ting, NASA Ames Research Center
Peter Tenenbaum, SETI Institute/NASA Ames Research Center
Jeffrey C. Smith, SETI Institute/NASA Ames Research Center
Bill Wohler, SETI Institute/NASA Ames Research Center
Mark Rose, NASA Ames Research Center
Chris Henze, NASA Ames Research Center
Michael Fausnaugh, Kavli Institute for Astrophysics and Space Science, Massachusetts Institute of Technology
Christopher Burke, Kavli Institute for Astrophysics and Space Science, Massachusetts Institute of Technology
Roland Vanderspek, Kavli Institute for Astrophysics and Space Science, Massachusetts Institute of Technology
Rebekah Hounsell, University of Maryland Baltimore County/NASA GSFC
The past eighteen months have seen a number of important changes for the TESS Science Processing Operations Center (SPOC) and our archival data products as TESS embarked upon its first extended mission. First, the SPOC developed and deployed a new 20-sec cadence pipeline, promising to unveil exciting new astrophysics at these short timescales for up to 1000 targets per observing sector. We also developed an FFI light curve pipeline that creates light curves and associated data products for up to 160,000 targets in each sector and archive these as High-Level Science Products (HLSP) at MAST. Soon we plan to perform transiting planet searches on these light curves and to release Data Validation reports and associated data products to the MAST. We also present results from the first multi-year transiting planet search of sectors 1 through 36. Finally, we discuss major changes to the SPOC pipeline that motivated the reprocessing of the first year of data, including the application of target- and cadence-specific scattered light flags, and an update to the sky background correction algorithm to mitigate bias in the original algorithm for dim and/or severely crowded stars.
TESS is funded by NASA’s Science Mission Directorate.
poster number: 3.24 | zenodo
Jonas Kemmer
(Landessternwarte, Zentrum für Astronomie der Universität Heidelberg)
J. Kemmer (Landessternwarte, Zentrum für Astronomie der Universität Heidelberg) + CARMENES Consortium et al., TBD
We present two small transiting planets with mass measurements orbiting bright mid M dwarfs (GJ 3473, GJ 3929). GJ 3473 b (Kemmer et al. 2020) is a hot, likely rocky, planet (P = 1.198 d, Mb = 1.86 ± 0.30 Me, and radius, Rb = 1.264 ± 0.050 Re), which is due to its high temperature a particularly attractive target for thermal emission spectroscopy. Further it is accompanied by another non-transiting planet (Pc = 15.509 ± 0.033 d) that has a minimum mass of Mc sin i = 7.41 ± 0.91 Me. For GJ 3929 b we present a preliminary analysis that yields a period of P = 2.616 d, mass Mb = 2.08 ± 0.63 Me, and radius, Rb = 1.147 ± 0.041 Re, which corresponds to a density that hints a high metal content of the planet. The radial velocity data show evidence for another signal, whose origin is, however, not yet clarified. Both systems add to the TESS level-one science goal to measure the masses for 50 transiting planets with radii smaller than 4 Re.
poster number: 4.01 | zenodo
José Rodrigues
(Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Portugal)
José Rodrigues, Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Portugal.
Susana C. C. Barros, Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Portugal.
Nuno C. Santos, Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Portugal
[Poster abstract] TESS is now routinely discovering new exoplanets and candidates (2647 TOIs in April 2021). Detailed analysis of the TESS lightcurves is necessary to select the best candidates for Radial Velocities (RV) follow-up as we cannot observe all TOIs due to the instrument time required. We developed a modular tool called "Follow-Up Lightcurves Multitool Assisting Radial velocities (FULMAR)" to help with this process. Our code compiles available TESS lightcurves for any selected target. It can filter the activity using different methods, compute the rotation period of the star using Gaussian Processes, search for transits in the cleaned lightcurve using BLS or TLS and probe signals that were detected with RV. FULMAR aims at helping astronomers involved in RV Follow-up of TESS candidates select their targets and speed their analysis up, requiring fewer observations per target and allowing for more of them to be characterized.
poster number: 4.02 | zenodo
Joseph Twicken
(SETI Institute / NASA Ames Research Center)
Jon M. Jenkins, NASA Ames Research Center; Lisa Kaltenegger, Carl Sagan Institute, Cornell University; Douglas A. Caldwell, SETI Institute / NASA Ames Research Center
In the Revised TESS Habitable Zone Catalog, Kaltenegger et al. (2021) identified the two-minute TESS target stars that were observed for sufficient duration over consecutive Primary Mission sectors to unambiguously capture a transit signature of planets orbiting in the Habitable Zone (HZ). The Catalog did not, however, identify the host stars for which transiting planets with HZ orbits and specified radii would be detectable based on the photometric precision of the retrieved light curves. We employ the Combined Differential Photometric Precision (CDPP) computed at 15 pulse durations in the Science Processing Operations Center (SPOC) transit searches of the Primary Mission light curves to estimate the signal-to-noise ratio (S/N) associated with transiting terrestrial planets (1.0 Re <= Rp <= 2.0 Re) in the HZ of the Catalog stars. We consider orbital periods under three HZ scenarios: Recent Venus, Earth Analog, and Early Mars. Given S/N, we further estimate the probability of detection of transiting terrestrial planets for each Catalog star and HZ scenario in the Primary Mission SPOC transit searches. We also present the expected yield by HZ scenario and planet radius under the assumption that all Catalog stars host such planets.
poster number: 4.03 | zenodo
Joshua Pepper
(Lehigh University)
Thomas Barclay - NASA Goddard Space Flight Center; University of Maryland, Baltimore County
Luke G. Bouma - Princeton University
Christopher J. Burke - Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology
Michael Fausnaugh - Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology
B. Scott Gaudi - The Ohio State University
Ryan J. Oelkers - Vanderbilt University
Keivan G. Stassun - Vanderbilt University; Fisk University
Joshua N. Winn - Princeton University
TESS is not a statistical mission, but the data present a valuable opportunity for studies of exoplanet populations. In order to conduct such studies, it is essential to understand the properties of the target sample - why were specific stars selected, others excluded, using what criteria. The TESS prime mission produced light curves for the 2-min target stars, and is producing a larger light curve catalog from a subset of the stars observed at the 30-min cadence. Both sets were assembled using information from the TIC, with the bulk of the 2-min targets drawn from the ranked CTL. Here we describe the global properties of both the 2-min and 30-min sets, including their physical parameters and their observational and variability characteristics from TESS related to transit detection. We review the "K dwarf desert", the trends of photometric precision with stellar type, and the implications of the difference between the CTL population and the actual 2-min cadence population.
poster number: 4.04 | zenodo
Justin Wittrock
(George Mason University)
Peter Plavchan, Diana Dragomir, Brett M. Morris, Ian J. M. Crossfield, Patrick Lowrance, James Ingalls, Brice-Olivier Demory, Thomas Barclay, Emily A. Gilbert, Peter Gao, Laurel Kaye, Songhu Wang, Elisabeth R. Newton, Eric Gaidos, Bryson L. Cale, Mohammed El Mufti, Kevin I. Collins, Michael Reefe, Stephen R. Kane, Angelle Tanner, Jonathan Gagné, Elisa V. Quintana, Laura D. Vega, Joshua E. Schlieder, Teresa Monsue, Leslie Hebb, Keivan G. Stassun, Veronica Roccatagliata, Richard P. Schwarz, T. G. Tan, Don J. Radford, Christopher Stockdale
AU Mic is a relatively bright, nearby (10 pc), young (22 Myr) M1V pre-main sequence star hosting at least two transiting exoplanets AU Mic b and c and a spatially-resolved outer dusty debris disk. This paper explores the transit timing variations (TTVs) of AU Mic b. We present three Spitzer/IRAC (4.5 μm) transits (two new), five TESS Cycle 1 and 3 transits, 11 LCO transits, one PEST transit, one Brierfield 0.36-m transit, and two transit timing measurements from Rossiter-McLaughlin observations of AU Mic b. We use ExoFASTv2 to jointly model the transits and to obtain the midpoint transit times. We then construct an O-C diagram to map the TTVs. We model the TTVs for AU Mic b with Exo-Striker to recover constraints on the mass for AU Mic c. We compare the TTV-derived constraints to a recent radial-velocity mass determination. The results demonstrate that the AU Mic planetary system is dynamically interacting, producing detectable TTVs, and the implied orbital dynamics may inform future constraints on the formation mechanisms for this young planetary system. We recommend future TTV observations of AU Mic b and c to further constrain the dynamical masses and to search for additional planets in the system.
poster number: 4.05 | zenodo
Kaiming Cui
(National Astronomical Observatories, Chinese Academy of Sciences)
Kaiming Cui (National Astronomical Observatories, Chinese Academy of Sciences), Jifeng Liu (National Astronomical Observatories, Chinese Academy of Sciences)
Modern astronomical studies with large volumn of data require advanced data reduction algorithms. Many deep learning methods have been widely used in light curve signal detection, like transits, eclipsing binaries, and flares. We put forward a noval algorithm for transit detection based on the mutural object detection method, which makes it intuitionistic and scalable.
poster number: 4.06 | zenodo
Kate Isaak
(European Space Agency/ESTEC)
The CHaracterising ExOPlanet Satellite is a small (s-class) mission in the Science Programme of ESA, implemented in partnership with Switzerland. Designed to provide ultra-high precision broadband photometry in the 330 - 1100nm waveband, CHEOPS has been in orbit since late December 2019 and is already living up to its potential for follow-up studies of known exoplanets. 80% of the observing time in the 3.5 year nominal mission lifetime is devoted to the Guaranteed Time Programme which is defined by the CHEOPS Science Team. The remaining 20% is available to the Community through ESA’s Guest Observers Programme. In this poster we give an overview of the opportunities that this programme presents.
poster number: 4.08 | zenodo
Kevin C. Schlaufman
(Johns Hopkins University)
Noah D. Halpern (Johns Hopkins University)
Planet occurrence and primordial atmospheric retention probability increase with period. The heavily irradiated short-period planets discovered by duration-limited transit surveys like that being executed by the Transiting Exoplanet Survey Satellite (TESS) may be very different from the lightly irradiated longer-period planets that are now known to be a much more common outcome of the planet formation process. We show that an occurrence-weighted mass--radius relation for the low-mass planets discovered so far by transit surveys orbiting solar-type stars requires both occurrence-weighted median Earth-mass and Neptune-mass planets to have a few percent of their masses in hydrogen/helium (H/He) atmospheres. It also implies core masses M_c in the range 2 M_Earth < M_c < 8 M_Earth that can retain their primordial atmospheres. In contrast to Uranus and Neptune that have at least 10% of their masses in H/He atmospheres, these occurrence-weighted median Neptune-mass planets are H/He poor. The implication is that they experienced collisions or formed in much shorter-lived and/or hotter parts of their parent protoplanetary disks than Uranus and Neptune's formation location in the protosolar nebula.
poster number: 4.09 | zenodo
Kingsley Kim
(1st Affiliation: Department of Physics & Astronomy, George Mason University, 4400 University Drive MS 3F3, Fairfax, VA 22030, USA 2nd Affiliation: Thomas Jefferson High School, for Science and Technology, 6560 Braddock Rd, Alexandria, VA 22312, USA)
Michael Reefe, Kevin Collins, Justin Wittrock, Michael Bowen, Owen Alfaro, Sudhish Chimaladinne, Kevin Eastridge, Caitlin Stibbards, Deven Combs, John Berberian, Mary Jimenez, Patrick Newman, David Vermilion, Srihan Kotnana, Shreyas Banaji, Natasha Latouf, Mohammed El Mufti, Peter Plavchan
We present follow-up observations of TESS targets conducted by our research group at George Mason University. Targets were observed nightly through a 0.8m telescope, and chosen through the SG1 TESS Transit Finder. Using AstroImageJ, a software package for image processing, our team reduced, platesolved and performed aperture photometry on images of targets. Apertures were chosen through accounting for seeing, nearby companions, and target brightness. Comparison stars were then reviewed, and target light curves were detrended using various observation parameters. AstroImageJ was used to run a NEB star check, and transits of the target were modeled through ExoFASTv2. Findings from this data analysis have contributed to multiple TOI detections and continue to expand the validation of candidates from the TESS mission.
poster number: 4.12 | zenodo
Lorena Acuña
(LAM, Aix-Marseille University)
Magali Deleuil (LAM, Aix-Marseille University)
Olivier Mousis (LAM, Aix-Marseille University)
Sergio Hoyer (LAM, Aix-Marseille University)
Theo Lopez (LAM, Aix-Marseille University)
Emmanuel Marcq (LATMOS, Sorbonne University)
Thierry Morel (STAR, Liege University)
Alexandre Santerne (LAM, Aix-Marseille University)
D. Gandolfi (Universita degli Studi di Torino)
D.J. Armstrong (University of Warwick)
The modelling of the internal structures of super-Earths and sub-Neptunes gives a valuable insight into their formation history and possible atmospheres. We present a planet model where the interior is coupled with the atmosphere within a Bayesian retrieval scheme. We take into account water in all its possible phases, including steam and supercritical phases, which is necessary for systems with a wide range of stellar irradiations. Our interior-atmosphere model calculates the compositional and atmospheric parameters, such as Fe and water content, surface pressures, scale heights and albedos. We analyse the highly-irradiated planet TOI-220 b, and the multiplanetary systems K2-138 and TRAPPIST-1. The very low density of TOI-220 b can only be explained with an extended atmosphere, which could be dominated by water or H/He as well. For TRAPPIST-1 and K2-138, we derive with their individual compositions a global increasing trend on the water content with increasing distance from the star in the inner region of the systems, while the planets in the outer region present a constant water mass fraction. This trend reveals the possible effects of migration, formation location and atmospheric mass loss during their formation history.
poster number: 4.13 | zenodo
Louise Dyregaard Nielsen
(Oxford University)
Francois Bouchy (Geneva Observatory), Nolan Grieves (Geneva Observatory)
Since the release of the first TESS sectors, the high resolution spectrograph CORALIE on the Swiss 1.2 m Euler telescope has observed more than 300 TESS Objects of Interest (TOIs). This work has been conducted in collaboration with the TESS Follow-up Programme to best support exoplanet-observations with larger telescopes, such as HARPS and Espresso. Within a wide range of science cases, we have covered a diverse set of TOIs spanning stellar types, orbital periods and transit depths. Amongst our sample of TOIs, we find that 43% are still unresolved planet candidates, 26% have been confirmed as planets, 2.5% are brown dwarfs and 20% have been identified as eclipsing stellar binaries. We wish to present an overview of the first three years of spectroscopic vetting and follow-up observations, with a focus on understanding the false positive rate in the TOI catalog. We will also demonstrate our latest data release of spectra, cross-correlation functions and radial velocities, which are publicly available through the DACE platform (dace.unige.ch).
poster number: 4.14 | zenodo
Lucas Brefka
(University of Michigan)
Juliette Becker (Caltech)
Ultra-short period (USP) planets are exoplanets which orbit within the magnetic truncation gap of their respective star. There are several known systems in which the USP planet in a multi-planet system orbits misaligned to the plane of the outer planets. TESS offers a unique opportunity to observe a large number of transiting systems and find these misaligned planets. With this poster I explore the unique parameters of such a system, hoping to answer the question of how such a geometry comes about. I explore the relationship between the inclination of the USP planet and the quadrupole moment (J2) of the star TOI-125, investigating whether this relationship is parameter-dependent by comparing it with the misaligned system K2-266. I used the secular perturbation theory to assess this effect of J2on inclination and determine the planets’ eigenfrequencies. N-body simulations were also used to test how the misalignment changes with changing J2, as stars tend to “spin down” with age. I intend to derive a better understanding of systems with misaligned USP planets and how these parameters can occur. This will also help to expand our knowledge of how systems evolve with time through an ever decreasing J2.
poster number: 4.15 | zenodo
Mallory Harris
(University of New Mexico)
Diana Dragomir (University of New Mexico), Steven Villanueva Jr. (MIT)
The Transiting Exoplanet Survey Satellite (TESS) is optimized to search nearby M dwarf stars for transiting extrasolar planets, providing new opportunities to study planets orbiting low-mass stars. I seek to take advantage of these opportunities by conducting a survey of the coldest planets in these systems to constrain their occurrence rates and find targets for future mass and atmospheric characterization. To identify these planets in the TESS (and K2) data, I have designed a pipeline to detect both single- and multiply-transiting long-period planets. Based on a simulated planet catalog (Barclay et al., 2018), I anticipate 27 single-transiting and 32 multiply-transiting M dwarf planets with P>20 days from the TESS primary mission. To vet targets, I am creating a convolution neural network using the novel method of converting light curves into Gramian Angular Difference Fields to better recognize transit patterns. As nearly half of the anticipated long-period planets will be detected as single-transits, I look to the TESS extended mission to recover additional transits, which will facilitate finding true periods using ground based follow-up. I will show preliminary results of my search of the first sectors of the TESS mission.
poster number: 4.16 | zenodo
Manthopoulou Eleni Evangelia
(University of Padova)
Nardiello Domenico (Laboratoire d'Astrophysique de Marseille)
Montalto Marco (University of Padova)
Piotto Giampaolo (University of Padova)
For the vast majority of exoplanets’ hosts the age is not well constrained and consequently planet properties, demographics and occurrence rates have been widely unmapped as a function of time. Discovering exoplanets in young associations and moving groups can shed light on these topics as they provide the opportunity to investigate the planet formation and evolution in environments with well defined age. The Full-Frame Images(FFIs) of TESS offer a huge data mining archive of millions of light curves to investigate. We present the analysis of ∼12k TESS light curves of stars, belonging to 41 young associations and moving groups, with ages spanning from 1 Myr to 680 Myr. We have extracted the light curves of young association’s members from the FFIs, corrected the systematic errors that affect them, and performed transit simulations to establish the performances of our technique to discover transit planet candidates. We report the detection of novel candidate exoplanets belonging to stellar associations with ages between 10 and 50 Myr.
poster number: 4.17 | zenodo
Marion Cointepas
(Institut de Planétologie et d'Astrophysique de Grenoble (IPAG))
Xavier Bonfils (IPAG), François Bouchy (Observatory of Geneva), Jose Almenara (IPAG)
ExTrA (Exoplanets in Transits and their Atmospheres - Bonfils et al. 2015) is a new instrument composed of an array of three 60-cm telescopes capable of infrared photometry and located in La Silla, Chile. This instrument relies on a new approach that involves combining optical photometry with spectroscopic information in order to mitigate the disruptive effect of Earth’s atmosphere, as well as effects introduced by instruments and detectors. ExTrA is currently being used to confirm TESS planet detections around M-dwarfs, refine transit parameters, and search for additional exoplanets in the same systems. ExTrA obtains a better precision for the planetary radius and for the transit timings for late M-type stars with one or a few TESS transits. This work already led to the confirmation of a mini-Neptune around the M-dwarf TOI-269 (Cointepas et al. 2021). ExTrA will also work in tandem with NIRPS, a near-infrared spectrograph that will join HARPS (High Accuracy Radial velocity Planet Searcher) on the 3.6m ESO telescope to conduct a comprehensive radial-velocity survey on M dwarfs.
poster number: 4.18 | zenodo
Marshall Johnson
(Las Cumbres Observatory)
TESS' all-sky survey enables studies of the demographics of exoplanets around stars too rare to have been observed in significant numbers by previous missions, or which were simply ignored by earlier observations. One such class is main sequence A stars, which are relatively rare and were mostly avoided by Kepler. Measuring the occurrence rate of short-period planets around these stars will inform our knowledge of planet formation and migration. Protoplanetary disks around A stars are more massive, shorter-lived, and have larger dust sublimation radii than those around FGKM stars. By comparing the short-period planetary population of A-type stars to those around FGKM stars, we can better understand the effects of these protoplanetary disk properties upon planet formation and migration. I will present initial results on the planetary occurrence rate for A stars from TESS, highlighting the particular challenges of confirming or validating these planets. Finally, I will discuss the consequences of these results for planet formation theory.
poster number: 4.19 | zenodo
Mathilde Timmermans
(University of Liege)
TFOP Sub-Group 1 is dedicated to the confirmation/rejection of TESS candidates with seeing-limited ground-based photometry. We present the contribution of the TRAPPIST and SPECULOOS networks of robotic telescopes to this effort. The two TRAPPIST 60cm telescopes and the six SPECULOOS 1m telescopes have pixel scales ~0.65 arcsec and ~0.35 arcsec, respectively. These telescopes can perform seeing-limited sub-mmag photometry for I-magitude ranging from 8.5 to 14 (for TRAPPIST) and from 9.5 to 15 (for SPECULOOS). Up to 50% of the TRAPPIST telescope time is dedicated to the TESS follow-up, and it has enabled so far the observation of more than 150 TESS candidates. Similarly, up to 20% of SPECULOOS observing time is dedicated to the TESS follow-up, with 22 candidates observed to this day. Finally, we present our latest results on TOI-2096, an M5 dwarf star hosting a system of two super-Earths close to 2:1 mean-motion resonance, confirmed using our facilities.
poster number: 4.20 | zenodo
Matthew Hooton
(University of Bern)
Matthew Hooton, Physikalisches Institut, University of Bern, Gesellsschaftstrasse 6, 3012 Bern, Switzerland
The asymmetric transit light curves of hot Jupiters orbiting fast-rotating, early type stars encode information about the true spin-orbit angle Ψ: a parameter that eludes measurement using most other methods. However, an accurate measurement of Ψ using from a transit is challenging, with numerous values for individual planets in literature exhibiting significant disagreement. Doppler tomography provides an alternative spectroscopy-based method which is less prone to bias, but only unlocks the sky-projected spin-orbit angle λ. I will present analyses of transit light curves for a sample of hot Jupiters with fast-rotating hosts acquired with CHEOPS, TESS, Kepler and Spitzer. The effect of fitting light curves acquired across the optical and IR with a single set of transit parameters greatly diminishes the degeneracies, and returns measurements of λ consistent with those from Doppler tomography. The placement of priors from tomography is better still, generally achieving improved precision on Ψ. With multi-colour light curves becoming available for ever-larger sections of the sky, this study provides a template for how to unveil the orbital architecture of these extreme systems and the underlying physical processes that shape them.
poster number: 4.21 | zenodo
Matthew R. Standing
(University of Birmingham)
Amaury H. M. J. Triaud - University of Birmingham
David V. Martin - Ohio State University
João P. Faria - Universidade do Porto
Jerome A. Orosz - San Diego State University
Veselin B. Kostov - NASA Goddard Space Flight Center
William F. Welsh - San Diego State University
Circumbinary planets, those which orbit both stars of a binary system, challenge our understanding of planet formation and orbital evolution. Planet formation around binary stars was thought to be difficult, and therefore these circumbinary planets were confined to the realm of science-fiction until the discovery of Kepler-16b in 2011. Since then, 13 circumbinary planets have been discovered in 11 systems by transit missions. TESS recently discovered its first and only confirmed circumbinary planet to date, TOI-1338b. Located in the mission’s continuous viewing zone and confirmed with ground-based photometry. Observed as part of the BEBOP (Binaries Escorted By Orbiting Planets) radial velocity survey, we combine ESPRESSO and HARPS radial velocity data in an attempt to confirm TOI-1338b and constrain it’s mass. With no sign of TOI-1338b in our current data we can place a 5-sigma upper limit on the mass at 20 Earth masses, a low-density planet. Here I will present our preliminary results on the system, including a candidate second planet in the system. If confirmed, this would make TOI-1338 the second ever multi-planetary circumbinary planet system, and the first circumbinary planet discovered by radial velocity data.
poster number: 4.22 | zenodo
Matthias Yang He
(Penn State)
Eric B. Ford (Penn State), Darin Ragozzine (Brigham Young University)
Population models of Kepler's multi-planet systems have revealed patterns in their underlying architectures, which can be used to make predictions about the presence of additional planets in systems with known transiting planets. I will describe how we use such a model (He et al 2020) to compute the conditional occurrence of planets given a Kepler-detectable planet. While unseen planets may potentially be discovered by radial velocity (RV) follow-up observations, they can also add a source of systematic error in efforts to fit the semi-amplitude (K) of the transiting planet. I will show that measuring the K of the transiting planet when there are an unknown number of planets often requires significantly more observations than in the ideal case (when there are no additional planets). Planets around 10 day periods, common among the TESS planet candidates, with sizes of 1-2 Earth radii and K comparable to the single-measurement RV precision typically require ~100 observations to measure their K to within 20% error, compared to only ~60 observations in the ideal case. These results highlight a previously unaccounted for source of error when measuring the masses of transiting planets with RVs, such as in the follow-up of TESS planets.
poster number: 4.23 | zenodo
Maura Lally
(Cornell University)
Andrew Vanderburg (UW Madison)
We reassess the claimed detection of variability in the atmosphere of the hot Jupiter HAT-P-7b, reported by Armstrong et al. (2016), using similar methods to look for time variation in the Kepler light curve of HAT-P-7. Using MCMC for phase curve fitting, we looked for statistically significant changes in the phase offset of HAT-P-7b’s phase curves over time. We identified apparently significant variations similar to those reported by Armstrong et al. (2016), and various tests confirmed the result to be mostly robust to different analysis strategies. However, when we injected non-varying phase curve signals into the light curves of similar stars and searched for variability using the same methods, we still found evidence for variability in those injected stationary phase curves. This suggests that un-modeled stellar or instrumental variability in the light curve may be contributing to the phase curve variation we measured for HAT-P-7b. Future studies seeking to detect time variability in photometric phase curves with telescopes like TESS should account for the impact of stellar variability on the measurements.
poster number: 4.24 | zenodo
Mayuko Mori
(University of Tokyo)
John Livingston (University of Tokyo), MuSCAT3 and IRD contributors, TFOP contributors
We present the discovery of a warm sub-Neptune around the M3 dwarf TIC 470381900 (TOI-1696), with a radius of 3.0 ± 0.2 Rearth and an orbital period of 2.5 days, using a combination of TESS and follow-up data. Simultaneous multi-band transit photometry from MuSCAT3 confirms the signal is achromatic and on-target, validating its planetary nature and refining the orbital ephemeris. High-resolution imaging with adaptive optics using Subaru/IRD and Gemini/’Alopeke shows no suspicious companion stars around the star. High-resolution spectroscopy from the Subaru / IRD rules out most spectroscopic binary scenarios. The expected planetary mass is 8-14 Mearth, corresponding to a radial velocity semi-amplitude 9-16 m/s. At J=12.2 mag, it is a promising target for atmospheric characterization with JWST, as well as potentially for mass measurement with NIR spectrographs.
poster number: 5.01 | zenodo
Melissa Janice Hobson
(Millennium Institute for Astrophysics / Instituto de Astrofisica, Pontificia Universidad Catolica de Chile)
Rafael Brahm, Millennium Institute for Astrophysics / Universidad Adolfo Ibanez, Chile
Nestor Espinoza, Space Telescope Science Institute, USA
Thomas Henning, Max-Planck-Institut fur Astronomie, Heidelberg, Germany
Andres Jordan, Millennium Institute for Astrophysics / Universidad Adolfo Ibanez, Chile
Diana Kossakowski, Max-Planck-Institut fur Astronomie, Heidelberg, Germany
Finja Reichardt, Max-Planck-Institut fur Astronomie, Heidelberg, Germany
Felipe Rojas, Millennium Institute for Astrophysics / Instituto de Astrofisica, Pontificia Universidad Catolica de Chile
Martin Schlecker, Max-Planck-Institut fur Astronomie, Heidelberg, Germany
Trifon Trifonov, Max-Planck-Institut fur Astronomie, Heidelberg, Germany
Giant, long-period exoplanets are vital to unveil the underlying physical picture of the leading planet formation and evolution theories. They are not only true relics of the planet formation process, maintaining the orbital and compositional properties with which they formed, but their radii also evolve without external irradiation such as that of the hot Jupiter population, providing rich and unique data for planet evolution models. Here we present the efforts of The Warm gIaNts with tEss collaboration (WINE), which is at the forefront of detecting, confirming, and characterizing transiting long-period giant exoplanets from TESS. This systematic search for these fascinating systems has given rise to hundreds of transiting giant candidates with periods larger than 10 days - out to hundreds of days - which is considerably enhancing and complementing the scientific output of the TESS mission. We'll introduce our efficient ground-based photometric and radial-velocity follow-up, which has helped confirm several tens of these candidates, including some of the most eccentric transiting long-period planets discovered to date, which are excellent candidates for future characterization studies.
poster number: 5.02 | zenodo
Michael Anthony Reefe
(George Mason University, Department of Physics and Astronomy)
Shawn Foster; Rochester Institute of Technology, Department of Physics and Astronomy
Owen Alfaro; George Mason University, Department of Physics and Astronomy
Nick Pepin; George Mason University, Department of Computer Science
Monica Vidaurri; NASA Goddard Space Flight Center
Taylor Ellingsen; George Mason University, Department of Physics and Astronomy
Justin Wittrock; George Mason University, Department of Physics and Astronomy
Patrick Newman; George Mason University, Department of Physics and Astronomy
Mary Jimenez; George Mason University, Department of Physics and Astronomy
Michael Bowen; George Mason University, Department of Physics and Astronomy
Deven Combs; George Mason University, Department of Physics and Astronomy
John Berberian; Woodson High School; George Mason University, Department of Physics and Astronomy
Natasha Latouf; George Mason University, Department of Physics and Astronomy
David Vermilion; NASA Goddard Space Flight Center; George Mason University, Department of Physics and Astronomy
Peter Plavchan; George Mason University, Department of Physics and Astronomy
We present a unique implementation of python coding in an asynchronous object-oriented framework to fully automate the process of collecting data with the George Mason University Observatory’s 0.8-meter telescope. The goal of this project is to streamline the process of collecting research data and monitoring weather, most often for follow-up observations for the TESS mission. We have automated slews and dome movements, CCD exposures, saving FITS images, focusing and guiding on the target, and taking calibration images (darks and flats). We also have automated periodically checking weather conditions to automate the decision-making involved in whether a shutdown is necessary. We are now able to input the specifications of the desired target in a user-friendly GUI that generates an input configuration file and launches the command-line code at the beginning of the night. The code, in its current state, has been tested and used for observations without error on at least 68 nights.
poster number: 5.03 | zenodo
Michele Silverstein
(NASA Goddard Space Flight Center)
Joshua E. Schlieder (NASA Goddard Space Flight Center), Thomas Barclay (University of Maryland, Baltimore County, NASA Goddard Space Flight Center), Benjamin J. Hord (University of Maryland, NASA Goddard Space Flight Center), Wei-Chun Jao (Georgia State University, RECONS Institute), Eliot H. Vrijmoet (Georgia State University, RECONS Institute), Todd Henry (RECONS Institute), Ryan Cloutier (Center for Astrophysics | Harvard & Smithsonian), Veselin B. Kostov (SETI Institute, NASA Goddard Space Flight Center), Ethan Kruse (NASA Goddard Space Flight Center), Jennifer G. Winters (Center for Astrophysics | Harvard & Smithsonian), Jonathan M. Irwin (Center for Astrophysics | Harvard & Smithsonian), Stephen Kane (University of California, Riverside), Keivan G. Stassun (Vanderbilt University), and other members of the TESS and HARPS teams.
We present the LHS 1678 (TOI-696) exoplanet system: two nearly Earth-sized transiting planets detected by TESS and a likely brown dwarf orbiting a bright M2 dwarf at 19.9 pc. The ultra-short period, inner planet (0.7 Earth radii, 0.9-day orbit) is a captivating target for emission spectroscopy observations with the JWST. The outer planet (1 Earth radii, 3.7-day orbit) is in the Venus-zone and may be Venus density: a promising target for greenhouse effect studies. Both planets are favorable targets for EPRV mass measurements and for JWST transmission spectroscopy observations to study their atmospheres. The substellar companion, detected via CTIO/SMARTS 0.9m astrometry, is on a decades-long orbit and may someday eclipse the host star, revealing a rare system architecture in which more and less massive objects orbit in the same plane. The host star is associated with an observed gap in the HR diagram tied to a change in M dwarf energy transport mechanisms. The effect of the associated stellar astrophysics on exoplanet evolution is currently unknown. In aggregate, LHS 1678 an exciting playground for comparative exoplanet science and understanding the formation and evolution of small, short-period exoplanets orbiting low-mass stars.
poster number: 5.04 | zenodo
Michelle Kunimoto
(MIT)
Tansu Daylan (MIT)
TESS has observed ~20 million stars brighter than Tmag ~ 13.5 in Full-Frame Images (FFIs), enabling a rich variety of exoplanet and stellar astrophysics investigations. The number of detectable exoplanets is expected to significantly increase towards fainter stars, given the factor of ~2 increase in the number of stars for each increase in TESS magnitude. However, there has not yet been a systematic search of all stars in FFIs down to these magnitudes, with current efforts focused on either brighter stars (Tmag < 10.5) or specific stellar types. In this presentation, I will provide the results of a search of faint stars observed in the Primary Mission using lightcurves extracted by the Quick Look Pipeline (QLP), as well as an ongoing search as the Extended Mission progresses. Of the thousands of new exoplanets uncovered, I will highlight planets most amenable to follow-up and of particular interest to the broad exoplanet community. Based on simulations of the TESS exoplanet yield, more than ~6000 exoplanets should be detectable in FFIs around stars between 10.5 < Tmag < 13.5 by the end of the current Extended Mission, which will significantly change the landscape of TESS exoplanets as we know it.
poster number: 5.05 | zenodo
Mohammed El Mufti
(George Mason University )
Mohammed El Mufti, Peter Plavchan, Bryson Cale, Michael Reefe, Angelle Tanner, Eric Gaidos, Rena Lee, Claire Geneser, Farzane Zohrabi, Ahmad Sohani, Kingsley Kim, Kevin Collins Issac, David James Vermilion, Catlin Stibbards, Shreyas Banaji, Jonathan Gagne, Peter Gao, Sharon Xuesong Wang, Johnanna Teske.
Main affiliation: Department of Physics & Astronomy, George Mason University, 4400 University Drive MS 3F3, Fairfax, VA 22030, USA
We present our program of obtaining precise near infrared (NIR) radial velocities (RVs) with the R ~ 80,000 iSHELL spectrograph on the NASA Infrared Telescope Facility (IRTF) using a methane isotopolgue absorption gas cell in the calibration unit. Observing cool low mass stars provides a “Habitable Zone'' shortcut through their lower mass, effective temperature, and larger reflex velocities from orbiting bodies. It is advantageous to observe these stars at NIR wavelengths where they emit the bulk of their bolometric luminosity and are most quiescent from rotationally modulated stellar activity. Our RV pipeline (pychell) extracts RVs by forward modeling the observed spectra, where the stellar template is derived iteratively using the target observations themselves through averaging barycenter-shifted residuals. With iSHELL, we have aided in the confirmation of seven TOI systems (K and M dwarfs) with notably small semi-amplitudes [3-15 m/s]. We further highlight results from our multi-year monitoring of AU Mic with a variety of facilities (incl. iSHELL) where we are able to robustly detect planets with semi-amplitudes more than an order of magnitude below the stellar-activity level.
poster number: 5.06 | zenodo
Mu-Tian Wang
(Nanjing University)
Hui-Gen Liu, Jia-Peng Zhu, Ji-Lin Zhou
Kepler Mission's single-band photometry suffers from astrophysical false positives (FPs), the most common of which are background eclipsing binaries (BEBs) and planets that are transiting the companion of the target star (companion transiting planets, CTPs). Multi-color photometry can reveal the color-dependent depth feature of FPs and thus exclude them. In this work, we aim to estimate how much the Kepler false positive rate would drop if a reference band (TESS, z, and Ks) were observing simultaneously with Kepler. We find that nearly 65-95% of the BEBs and more than 80% of the CTPs with Jupiter-size planets will show detectable depth variations if the reference band can achieve a Kepler-like photometric precision. We also apply the multi-color model to calculate the false positive probability (FPP) of small planet candidates, which alleviates the photometric precisions required to resolve the depth difference of FPs. Additionally, we show that the FPP calculation helps distinguish the planet candidate's host star in an unresolved binary system. The analysis framework of this work can be easily adapted to predict the multi-color photometry yield for other transit surveys, especially for TESS Mission.
poster number: 5.07 | zenodo
Noah D. Vowell
(Michigan State University )
Joseph E. Rodriguez (Michigan State University), Paul A. Dalba (University of California Santa Cruz)
The traditional boundary between brown dwarfs and M-dwarfs is a mass limit for sustainable hydrogen fusion (~80 MJ). Discovering and characterizing objects near this transition point offers a unique opportunity to test our substellar and stellar evolution models, while studying the nature of this transition. Using observations from Kepler, combined with ground-based radial velocity measurements from Keck-HIRES and APOGEE, we confirmed and measured the mass of Kepler-807 B. This companion is on a highly eccentric (0.68) 117 day orbit, and from our analysis we measured a radius of 0.995 ± 0.049 RJ and a mass of 83.3 ± 3.9 MJ, too massive to be an exoplanet as previously characterized. This system is part of the Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey to discover and characterize long period giant planets in Kepler, K2, and TESS. I will discuss the characterization of Kepler-807 B, and place it in the context of ongoing efforts to better understand the transition between brown dwarfs and stars.
poster number: 5.08 | zenodo
Nuno Miguel P. C. Rosário
(Instituto de Astrofısica e Ciencias do Espaco, Universidade do Porto, CAUP, Porto, Portugal / Departamento de Fısica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal)
Susana C. C. Barros (Instituto de Astrofısica e Ciencias do Espaco, Universidade do Porto, CAUP, Porto, Portugal / Departamento de Fısica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal)
Olivier Demangeon (Instituto de Astrofısica e Ciencias do Espaco, Universidade do Porto, CAUP, Porto, Portugal / Departamento de Fısica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal / Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France)
Nuno C. Santos (Instituto de Astrofısica e Ciencias do Espaco, Universidade do Porto, CAUP, Porto, Portugal / Departamento de Fısica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal)
Babatunde Akinsanmi (Instituto de Astrofısica e Ciencias do Espaco, Universidade do Porto, CAUP, Porto, Portugal / Departamento de Fısica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal)
Tidal interaction between a star and a close-in exoplanet leads to shrinkage of the planetary orbit and eventual tidal disruption of the planet. For some of the known exoplanets the expected orbital period variation due to tides is observable over 10 years and they are expected to have measurable tidal decay at date of publication. We analyze TESS data for some targets known to host close-in hot-Jupiters. We aim to measure the current limits on tidal decay which will provide new constrains on the modified tidal quality factor Q*'. We fit all light curves together for each target and obtain new transit timings and new planet parameters. We use previously published timings with our results to fit the change in period with a quadratic ephemerides model. We obtain new minimum values for Q*' of several hot-Jupiters expected to show orbital decay. We improve the precision on the known planet parameters for our targets with recent observations from TESS. We observe a period change in most targets but we still do not have enough precision to constrain Q*' significantly. We expect further observations to improve the precision and confirm our results on these targets.
poster number: 5.09 | zenodo
Paz Bluhm
(Landessternwarte (LSW) Heidelberg University)
E. Pallé (nstituto de Astrofísica de Canarias (IAC), E-38200 La Laguna,Tenerife, Spain , and Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain), K. Molaverdikhani (Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany), J. Kemmer (Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany), A. P. Hatzes (Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany). et al. 2021
We report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685. We confirm the planetary nature of the transit signal, which has a period of Pb= 0.6691403 +/- 0.000002 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of Mb= 3.78 +/- 0.63 M_Earth, a radius of Rb=1.70+/- 0.07 R_Earth, which together result in a bulk density of 4.21+/-0.9 g/cm^3, and an equilibrium temperature of about 1069 K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 [c], which has an orbital period of about 9.02 d.
poster number: 5.10 | zenodo
Petr Kabáth
(Astronomical Institute of Czech Academy of Sciences)
Petr Kabáth and the KESPRINT team
We will report on the spectroscopic follow-up of TESS planetary candidates with a network of 2-3 meter telescopes located in Ondrejov, CZ, Tautenburg, DE, McDonald observatory, US and SMARTS telescope, CL, which use spectrographs with high resolving power. We coordinate our observing campaigns within the KESPRINT consortium and we significantly contribute to validation and characterization of mostly gas giant planets but not only. Results of our observing campaigns from 2020-2021 will be presented. We will also briefly discuss our future plans.
poster number: 5.11 | zenodo
Pierre-Cécil König
(European Southern Observatory)
Guillaume Hébrard (Institut d'Astrophysique de Paris, France), Gaitee Hussain (European Space Research and Technology Centre, Netherlands), Paulo Miles-Páez (European Southern Observatory, Germany), Mario Damasso (Istituto Nazionale di Astrofisica, Italy), Luca Naponiello (Istituto Nazionale di Astrofisica, Italy), Aldo Bonomo (Istituto Nazionale di Astrofisica, Italy), Alessandro Sozzetti (Istituto Nazionale di Astrofisica, Italy)
We report the detection of a new transiting extrasolar planet candidate identified as TOI-1710.01 by the Transiting Exoplanet Survey Satellite (TESS). Its planetary nature has been confirmed from HARPS-N and SOPHIE spectroscopic observations via the radial velocity method. The stellar parameters for the host star are derived from HARPS-N spectra and a joint Markov chain Monte Carlo (MCMC) adjustment of the spectral energy distribution and evolutionary tracks of TOI-1710. Performed in a combined MCMC and quasi-periodic Gaussian process method, a simultaneous analysis of the TESS light curve and the radial velocity evolution concomitantly allows to determine the planetary properties and inspect the stellar magnetic activity jitter. TOI-1710b is a massive Neptune (31.8±5.9 M_Earth and 5.84±0.30 R_Earth) orbiting a G5VI subdwarf star on a 24.3 days almost circular orbit (e=0.14±0.08).
poster number: 5.13 | zenodo
Rachel B. Fernandes
(Lunar and Planetary Laboratory, The University of Arizona)
Gijs D. Mulders - Universidad Adolfo Ibáñez, Chile
Ilaria Pascucci - The University of Arizona
While Kepler discovered a large number of exoplanets close to their star, the lower detectability toward small planet radii and large orbital periods resulted in the detection of just one Earth-size planet in the habitable zone of a solar analogue. Hence, determining the frequency of habitable zone Earth-size planets, hereafter EtaEarth, requires extrapolations based on the more abundant population of close-in, small planets. However, it is known that this population is contaminated by stripped cores of once sub-Neptune planets. Here, we show that when considering only planets beyond 30 days, where stripping mechanisms become inefficient, the value of EtaEarth drops from 40% to ~5-10%. Thus, quantifying the contamination of sub-Neptunes to the small, close-in planets becomes crucial to obtain a more reliable EtaEarth estimate. One way to quantify this contamination is by measuring the occurrence of primordial sub-Neptunes in young clusters (< 1 Gyr), before their envelope is stripped away. We will present our ongoing effort with TESS to de-contaminate the short-period small planet population from photoevaporated mini-Neptunes and thus provide more reliable estimates of EtaEarth.
poster number: 5.15 | zenodo
Rebekah Dawson
(Penn State)
Warm, large exoplanets with 10-100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Precise characterization of their masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the TOI 216 system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV baseline from TESS and an ongoing ground-based transit observing campaign increase the precision of the mass and eccentricity measurements. We determine that TOI-216c is a warm Jupiter, TOI-216b is an eccentric warm Neptune, and that they librate in 2:1 resonance with a moderate libration amplitude, a small but significant free eccentricity, and a small but significant mutual inclination. The libration amplitude, free eccentricity, and mutual inclination imply a disturbance of TOI-216b before or after resonance capture, perhaps by an undetected third planet. We discuss the implications for the origins of warm, large exoplanets.
poster number: 5.16 | zenodo
Rob Wittenmyer
(MINERVA Observatory, University of Southern Queensland)
Duncan Wright (USQ), Brett Addison (USQ), George Zhou (USQ), Stephen Kane (UC Riverside), John Kielkopf (Louisville), Peter Plavchan (George Mason), Avi Shporer (MIT), Brendan Bowler (UT-Austin), Jonathan Horner (USQ), Chris Tinney (UNSW), Hui Zhang (SHAO), Tim Bedding (USyd), Sarah Ballard (Florida)
MINERVA-Australis at the University of Southern Queensland's Mount Kent Observatory is the only southern hemisphere precise radial velocity facility wholly dedicated to follow-up of TESS planets. MINERVA-Australis is a partnership between MIT, UNSW Sydney, George Mason University, University of Louisville, Nanjing University, UC-Riverside, University of Texas, and the University of Florida. Observing time is also available to the US community via NSF NOIRLab proposal calls. Being fully robotic, we have been unaffected by Covid-19 closures. We have contributed data to the validation of 23 TESS planets. I give an overview and update of operations, highlighting our recent mass measurements for TOI-778 and TOI-1842. I also describe our new photometric capabilities, aiming to validate small TESS planets and to rescue planets from ephemeris erosion.
poster number: 5.17 | zenodo
Sam Christian
(Liberal Arts and Science Academy)
Andrew Vanderburg, University of Wisconsin; Juliette Becker, Caltech; Daniel Yahalomi, Columbia University; Logan Pearce, University of Arizona; George Zhou, Center for Astrophysics; Karen Collins, Center for Astrophysics; Adam Kraus, University of Texas at Austin
Astronomers do not have a complete picture of the effects of wide-binary systems on the formation and evolution of exoplanets. We investigate these effects using new data from Gaia EDR3 and the TESS mission to characterize wide-binary systems with transiting exoplanets. We identify a sample of 67 systems of transiting exoplanet candidates (with well-determined orbital inclinations) that reside in wide visual binary systems. We derive orbital parameters for the wide-binary systems and measure the minimum difference in orbital inclination between the binary and planet orbits. We determine that there appears to be a statistically significant difference in the inclination distribution of wide-binary stars with transiting planets compared to a control sample (p=0.0014). This implies that there might be a population of planets in binary systems whose orbits are aligned with those of the binary. The population of aligned systems appears to be predominantly in systems with binary semimajor axes less than 700 AU. We investigate some effects that could cause such an alignment, such as a primordial alignment of angular momentum vectors of the binary system or a torque caused by a misaligned binary companion.
poster number: 5.18 | zenodo
Samuel N Quinn
(Center for Astrophysics | Harvard & Smithsonian)
Jonti Horner (University of Southern Queensland),
Karen A. Collins (Center for Astrophysics | Harvard & Smithsonian),
Jason D. Eastman (Center for Astrophysics | Harvard & Smithsonian),
Laura Kreidberg (Max-Planck-Institut für Astronomie),
Andrew Vanderburg (University of Wisconsin-Madison),
George Zhou (University of Southern Queensland),
R. Paul Butler (Earth and Planets Laboratory, Carnegie Institution for Science),
Jeffrey D. Crane (Observatories of the Carnegie Institution for Science),
Stephen A. Shectman (Observatories of the Carnegie Institution for Science),
Johanna K. Teske (Earth and Planets Laboratory, Carnegie Institution for Science),
Ian B. Thompson (Observatories of the Carnegie Institution for Science),
Sharon Xuesong Wang (Tsinghua University),
Robert A. Wittenmyer (University of Southern Queensland),
The TESS spacecraft detected transits of the G star HD 97260 (TOI-682), implying the presence of a planet with a radius of 3.46 Re and an orbital period of 6.84 days. We confirm the planet using radial velocities from the Planet Finder Spectrograph and measure its mass to be 12.3 Me. A second radial-velocity signal with a period of 16.1 days corresponds to a non-transiting planet with a minimum mass of 9.4 Me. We explore the dynamical interaction between the planets, which display significant non-zero eccentricities, and discuss the prospects for future characterization. In particular, HD 97260 b has an equilibrium temperature of 950 K, where relatively few atmospheres of Neptune-sized planets have been characterized. The transit depth (1100 ppm), modest density (1.64 g/cm^3), and brightness of the host star (V=10.0; H=8.2) should lead to high-S/N transmission spectroscopy.
poster number: 5.19 | zenodo
Sascha Grziwa
(RIU-PF, University of Cologne)
Martin Paetzold, RIU-PF, at the University of Cologne
TESS has found many new exoplanets and has enriched our knowledge in this field. Most of these exoplanets have relative short orbital periods due to the observation technique of TESS. A statistical comparison of the detected periodic transits in TESS light curves with the detected periodic transits in the longer KEPLER light curves reveals that TESS light curves should show many additional single transit events which are not detected so far. Single transits of Jupiter-size planets are regularly found while single transits of Neptune- or Earth-size planets are rarely detected. The detection of single transits can reveal long orbital period planet candidates attractive for follow-up observations, revisits or additional photometric observations (e.g. CHEOPS). The Rhenish Institute for Environmental Research, department of Planetary Research, at the University of Cologne (RIU-PF) is developing the dedicated pipeline SINGLETRANS to search for single transit events of small planets in light curves. SINGLETRANS is a wavelet based transient search algorithm and shall complement our well-established detection pipeline EXOTRANS. SINGLETRANS shall also detect quasi-periodic transits (planets showing strong TTV, circumbinary planets).
poster number: 5.20 | zenodo
Serena Benatti
(INAF - Astronomical Observatory of Palermo)
S. Benatti (INAF-Astronomical Observatory of Palermo), I. Carleo (Wesleyan University), S. Desidera (INAF-Astronomical Observatory of Padova)
The GAPS project gathers a large part of the Italian community working on exoplanets. One of our aims is the search for young exoplanets with HARPS-N at TNG, since they are the key targets to study the early evolution of planetary systems and to understand the origin of their observed diversity. The TESS space mission is deeply changing our view of young planets at close separations and provides robust candidates that we are following-up within GAPS and other dedicated programs. We analyzed the HARPS-N RV data of TOI-942 (age 30-80 Myr) as well as the TESS light curve, which allowed us to validate the candidate and detect an additional transiting planet. TOI-942 b and c are both hot-Neptunes, with a period of 4 and 10 days, respectively. This is the youngest multi-planet system identified by TESS so far. We also measured a mass upper limit for the 40 Myr old planet DS Tuc A b (TOI-200) indicating a very low density for this Neptune-size planet. We also modelled the Rossiter-McLaughlin effect with ESPRESSO data showing that the orbit is not completely aligned and simulated the effects of photoevaporation on the planet's atmosphere. Other works are in preparation for the validation and characterization of additional young TOIs.
poster number: 5.21 | zenodo
Shashank Dholakia
(University of California, Berkeley)
Rodrigo Luger (Flatiron Center for Computational Astrophysics), Shishir Dholakia (UC Berkeley)
Exoplanets that transit rapidly-rotating stars can be a unique tool to learn about the dynamical history of exoplanet systems photometrically. Two rotational effects on such stars are oblateness and gravity darkening, where the poles are hotter and more luminous than the equator due to latitude-dependent stellar surface gravity. Both of these effects break spherical symmetry and can allow a photometric measurement of the true spin-orbit angle of the system. We create a fast, analytic transit model in the starry package that incorporate these effects. We model gravity darkening using a spherical harmonic expansion of the Von Zeipel Law to arbitrary order. We take into account stellar oblateness by modeling the star as an ellipse in projection. Using Green’s theorem, we write the 2D flux integral first as an equivalent 1D integral around the projected boundary of the star and planet. We then solve this integral analytically. The implementation in starry is fast enough and well suited to posterior inference. We note its use as a complement to spectroscopic measurements that provide the projected spin-orbit angle and also as a standalone method to constrain spin-orbit angles photometrically for hundreds of such systems in TESS.
poster number: 5.22 | zenodo
Solène Ulmer-Moll
(Geneva Observatory)
M. Lendl (Geneva Observatory)
Warm Jupiters provide the opportunity to better understand the formation and evolution of planetary systems. Their atmospheric properties remain largely unaltered by the impact of the host star, and their orbital arrangement reflects a migrational history different from close-in objects. Warm Jupiters are known to cover a wide range of eccentricities however it is unclear which are the dominant formation pathways to explain this observation. Increasing the sample of long-period exoplanets with known radii is thus crucial. In this talk, I report the discovery of two massive warm Jupiter-size planets on eccentric orbits. Detected as single transit events in the TESS primary mission, only TIC 124029677 presents a second transit in the extended mission. However NGTS monitored TIC 257527578 and detected a second transit.Interestingly, candidates with two transits separated by almost two years present a set of discrete period aliases which enables a more efficient photometric follow-up. Radial velocity follow up was performed with several high-resolution spectrographs. I conclude with an outlook on the potential of these targets for follow-up studies of the planetary atmosphere as both warm Jupiters orbit reasonably bright host stars.
poster number: 5.23 | zenodo
Stephanie Yoshida
(Harvard College)
Samuel Grunblatt, American Museum of Natural History & Center for Computational Astrophysics, Flatiron Institute
The search for planets orbiting other stars has expanded to include stars from galaxies other than the Milky Way. Claims of extragalactic planets have been heavily debated in the past. With the recent survey launches, a sample of lightcurves and stellar kinematic measurements could be used to identify planet candidates around stars of extragalactic origin. In this study, 1,080 evolved stars observed by Gaia and TESS missions with kinematics suggestive of extragalactic origin were searched for planet transits. Injection-recovery tests were performed to measure the TESS data sensitivity and the sample completeness. Although no planet transits were detected, the limits found on planet occurrence are consistent with previous studies of planet occurrence around similar host stars. However, metallicity and planet occurrence tend to be strongly correlated, therefore, finding a planet around this star population may be more difficult, as halo stars tend to be lower metallicity. It is also likely that some of the stars in our sample do not originate from other galaxies. Thus, we predict 10,000-30,000 stars must be searched to detect a planet of extragalactic origin, potentially possible with future TESS and Gaia data.
poster number: 5.24 | zenodo
Steven Giacalone
(UC Berkeley)
Courtney Dressing (UC Berkeley)
Validation has played an important role in the discovery of planets detected by TESS. This process of scrutinizing a planet candidate typically involves an analysis of TESS photometry and a combination of different follow-up observations that rule out sources of astrophysical false positives. Despite its usefulness, validation of TESS planet candidates often lacks a robust statistical framework with which to argue for the existence of a planet. We present TRICERATOPS, an easy-to-use tool that resolves this shortcoming using a Bayesian probability calculation. By combining data from TESS and ground-based facilities, our tool quantifies the chance of a transit-like signal originating from both known and unresolved stars located near the potential planet-hosting star on the sky. We display that these quantities reliably predict which candidates are bona fide planets and which candidates are astrophysical false positives, such as nearby eclipsing binaries. We also discuss contexts in which validation with TRICERATOPS is particularly valuable, such as the discovery of planets around stars poorly suited for precise radial velocity measurements.
poster number: 6.01 | zenodo
Sydney Vach
(Harvard University)
Samuel N. Quinn (Center for Astrophysics | Harvard & Smithsonian),
Andrew Vanderburg (Department of Astronomy, University of Wisconsin-Madison)
Most of the significant changes in planetary evolution occur within the first billion years. Observing young planetary systems allows us to understand the physical mechanisms driving these changes in ways that observations of mature planets cannot. Transit surveys have begun to discover young planets, but mostly have been limited to faint, short-period systems. As an all-sky survey, TESS is able to detect the brightest and rarest types of transiting planetary systems. Here, we report the discovery of a young, multi-planet system orbiting the bright K4.5V star, TOI-712 (V = 10.8, M* = 0.73 Msun, R* = 0.67 Rsun, Teff = 4633 K). From the TESS light curve, we measure a rotation period of ~12.6 days, and an approximate age of 500 Myr. The photometric observations reveal three small transiting planets (Rb = 2.3 Re, Rc = 2.7 Re, Rd = 2.5 Re), with orbital periods of Pb = 9.5 days, Pc = 51.7 days, and Pd = 84.8 days. We calculate that the habitable zone falls between 83 and 325 days, placing TOI-712d near its inner edge. Among known planetary systems, TOI-712 stands out as young, long period, and bright, which will facilitate further characterization.
poster number: 6.02 | zenodo
Thomas M. Esposito
(SETI Institute)
Franck Marchis (SETI Institute), Dan Peluso (University of Southern Queensland), Arin Avsar (SETI Institute), Robert T. Zellem (NASA JPL)
Since June 2020, citizen scientists have been measuring TESS planet candidate light curves from backyards and rooftops around the world as members of the Unistellar eVscope Network under the aegis of SETI Institute astronomers. We have detected 32 complete or partial transits by "planet candidate" TOI's from 117 observations by over 40 citizen scientists, as of April 2021. These range down to transit depths of 1.0% (i.e., Jupiters around Sun-like stars) and host V=14 mag, and produce mid-transit time measurements precise to a few minutes with a single 4.5-inch telescope. We are contributing our photometric data to public databases (e.g., AAVSO Exoplanet Database) and coordinating observations with the TESS Follow-up Observation Program and NASA's Exoplanet Watch (Zellem+ 2020). Thus, we will rule out false positives and confirm orbits of short-period Jupiter-sized TOI's (>200 meet our detection criteria) and monitor long period (P>100 days) candidates with few observed transits for transit timing variations; potentially saving hundreds of hours for future characterization missions by maintaining ephemerides. We will present an overview of the eVscope, our observing strategy and citizen scientist community, and light curve results.
poster number: 6.03 | zenodo
Vineet Kumar Mannaday
(Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.), India)
Vineet Kumar Mannaday (Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India), Parijat Thakur (Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India), D. K. Sahu (Indian Institute of Astrophysics, Bangalore-560034, India), Ing-Guey Jiang (Department of Physics and Institute of Astronomy, National Tsing-Hua University, Hsinchu, Taiwan), John Southworth (Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK), Luigi Mancini (Max Planck Institute for Astronomy, Königstuh l17, D-69117 Heidelberg, Germany), Martin Vanko (Astronomical Institute, Slovak Academy of Sciences, SK-059 60 Tatranská Lomnica, Slovakia), Emil Kundra (Astronomical Institute, Slovak Academy of Sciences, SK-059 60 Tatranská Lomnica, Slovakia), Pavol Gajdoš (Institute of Physics, Faculty of Science, Pavol Jozef Sáfrik University, Košice, Slovakia), Li-Hsin Su (Department of Physics and Institute of Astronomy, National Tsing-Hua University, Hsinchu, Taiwan), Devesh P. Sariya (Department of Physics and Institute of Astronomy, National Tsing-Hua University, Hsinchu, Taiwan), Li-Chin Yeh (Institute of Computational and Modeling Science, National Tsing-Hua University, Hsinchu, Taiwan)
We have investigated the possibility of transit timing variation (TTV) and its plausible cause in the hot-Jupiter systems TrES-3 and Qatar-1. In this study, total160 transit light curves of TrES-3b and 197 transit light curves of Qatar-1b are considered. Using the mid-transit times determined from these light curves, we have improved the transit ephemeris for both these hot-Jupiters. Our timing analysis show the presence of TTVs in these planetary systems that are unlikely to be periodic. To explore the possibility of a long-term TTVs, the orbital decay model was fitted to transit timing data which reveals the period change of 2.71 ± 1.49 ms/yr and 12.39 ± 2.74 ms/yr for TrES-3b and Qatar-1b, respectively. It is worth to mention here that we have observed increasing period for both hot-Jupiters in contrast to the previous results available in literature. Because of the statistically less significant estimate of period change of TrES-3b, we prefer a linear ephemeris model over the decay model. However, the linear model does not appear to represent the transit data of Qatar-1b considered here as the observed change in period is highly significant. This change may not be attributed to orbital decay and there may be some other plausible reasons such as presence of a third body in wider orbit and the apsidal precession.
poster number: 6.04 | zenodo
William Misener
(University of California, Los Angeles)
Hilke Schlichting (UCLA)
Super-Earths will constitute a large portion of the small exoplanets well-suited for detailed atmospheric characterization that TESS aims to discover. Current theory predicts these planets accreted large nebular hydrogen/helium envelopes before disk dispersal, which have since been mostly lost through hydrodynamic outflows. The effects of this early evolution on super-Earths’ long-term atmospheric mass, composition, and redox state are largely unexplored, despite potential ramifications for both the habitability and atmospheric observability of this common class of planets. I present the observable outcomes of the atmospheric evolution of super-Earths undergoing core-powered mass loss. Using theoretical models, I demonstrate that loss of the primordial atmosphere can be incomplete, leading to a small residual H/He envelope. The masses of these remnant atmospheres vary by orders of magnitude depending on the planet's mass and the flux received from its host star. Super-Earths finish mass loss with retained atmospheric masses ranging from 10^-8 to 10^-3 planet masses for typical super-Earth parameters. I discuss how this residual hydrogen affects the composition and enhances potential observational signatures of these atmospheres.
poster number: 6.06 | zenodo
Xinyan Hua
(Tsinghua University)
Sharon Xuesong Wang, Tsinghua University; Johanna K. Teske, Carnegie EPL; Angie Wolfgang, Penn State University; and the MTS team
We present a TESS discovered planetary system with a short-period sub-Neptune, HD 307842 (or TOI 784), to confirm and characterize its distant gas giant companion using radial velocity (RV) observations. Observations and simulations both hint in correlations between inner planet properties and the presence or absence of an outer companion. Our program investigates such links between the long-period giants and inner small planets by systematically search and characterize giant planets in systems with known transiting planets. HD 307842 is a V = 9.4 solar-type mid-G star observed by TESS. Transiting data shows that around HD 307842, there is one planet candidate TOI 784.01 with period P = 2.8 days and R = 1.86 $R_{Earth}$. The radial velocity measurements by the Magellan/PFS suggest that there is likely an additional long-period planet in the system. In this work, we aim to confirm the outer long-period planet or at least give constraints on its properties. The preliminary RV fitting results suggest an orbital period ~110 days and a minimum mass of ~90 $M_{Earth}$. Next, we will collect more RV data from Magellan/PFS and LCOGT/NRES to map out the entire orbit of the giant planet candidate.
poster number: 6.07 | zenodo
Zoe L. de Beurs
(University of Texas at Austin)
Andrew Vanderburg [1], Christopher J. Shallue [2], Joseph E. Rodriguez [3], Sebastian Zieba [4], Annelies Mortier [5, 6], Lars Buchave [7], Luca Malavolta [8], and the HARPS-N Collaboration
Affiliations
1. Department of Astronomy, University of Wisconsin-Madison, Madison, WI, 53706, USA
2. Center for Astrophysics | Harvard & Smithsonian (CfA), 60 Garden St., Cambridge, MA 02138, USA
3. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
4. Max-Planck-Institut für Astronomie (MPIA), Königstuhl 17, 69117 Heidelberg, Germany
5. Astrophysics Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
6. Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
7. DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 328, DK-2800 Kgs. Lyngby, Denmark
8. Dipartimento di Fisica e Astronomia ``Galileo Galilei'', Università di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova, Italy
We report precise radial velocity observations of HD 212657 (= K2-167), a star shown by K2 to host a transiting planet in a 9.97857 day orbit. Using observations from TESS, we refined planet parameters, especially the orbital period. We collected 76 precise radial velocity observations with the HARPS-N spectrograph between August 2015 and October 2016. Although this planet was first found using the transit method in 2015 and validated in 2018, stellar jitter originally limited our ability to measure its mass. In this work, we demonstrate that a new machine learning inspired method can successfully mitigate stellar jitter and reveal the mass of K2-167 b. In the future, these or similar techniques could be widely applied to solar-type (FGK) stars, help measure masses of planets from TESS to fulfill the level 1 science requirement, and eventually help detect habitable-zone Earth-mass exoplanets.
poster number: 6.08 | zenodo
Helena Treiber
(University of Hawaii-Manoa IfA and Amherst College)
Jason T. Hinkle (IfA), Benjamin J. Shappee (IfA), Michael M. Fausnaugh (MIT), Patrick J. Vallely (OSU)
We present the results of a systematic search for AGN in TESS light curves of dwarf galaxies. Evidence of short-term flux changes in dwarf galaxies can reveal an AGN even when emission line ratios fail to do so. Studies of dwarf AGN are essential for a general understanding of the relationship between black hole and galaxy evolution. The timescale from the commonly-used damped random walk model has been shown to correlate with black hole mass, but further studies are required to understand the physical processes driving this empirical model’s effectiveness. Partially because of this timescale relation, TESS is a unique tool for the identification of dwarf AGN; a light curve from a single sector can reveal adequate variability. We demonstrate a successful methodology that accounts for TESS systematics and contamination by variable stars. The newly-identified AGN help populate scaling relations at the low-mass end and demonstrate the crucial role of TESS in studies of dwarf AGN and AGN in general.
poster number: 6.09 | zenodo
Qinan Wang
(johns hopkins university)
Ryan Ridden-Harper Johns Hopkins University
Ashley Villar Columbia University
Armin Rest Space Telescope Science Institute, Johns Hopkins University
Yossef Zenati Johns Hopkins University
Sofia Rest Johns Hopkins University
Georgios Dimitriadis Trinity College Dublin
Ryan Foley UC Santa Cruz
Despite their fundamental importance to cosmology, the exact progenitor systems of type Ia supernovae (SNe Ia) are not known. Theories suggest that signatures of some SNe Ia progenitors could be seen as bumps or flux excess in the early light curve, e.g. the collision of SN ejecta with the non-degenerate binary companion (Kasen 2010). With high cadence, and well calibrated TESS light curves, we can search for such signals to identify progenitor systems of SNe Ia and estimate relative rates of different progenitor systems. Understanding this will have significant implications for cosmological measurements, as systematic uncertainties correlated with SNe Ia begin to dominate calculations. With SNe Ia in Kepler, such as SN 2018oh and SN 2018agk, we analyzed efficiency and contamination in bump detection routines and developed robust techniques for detecting and modelling early excess features, which can be directly applied to TESS. In this talk we present our analysis methods and apply them to high quality Kepler and TESS SNe Ia. With our novel bump detection method, we can turn TESS into a powerful and unique tool for supernovae science and cosmology.
poster number: 6.10 | zenodo
Rajesh Kumar Dubey
(Lovely Professional University)
Shankar Dayal Patak, Lovely Professionak
The local universe expansion rate is one of the most fundamental and essential cosmological parameters. This value which is known by the name of Hubble’s Constant is scientifically measured by electromagnetic sources called distance ladder. Surprisingly, using Gravitational Wave (GW) analysis this value can be measured making GW sources another significant method to act as standard sirens with their electromagnetic counterparts from their host galaxy. The gravitational wave event GW 170817 was the outcome of the merger of two different neutron stars. The electromagnetic event was recorded from the host galaxy NGC4993. The GW170817 has been a considerable success in this direction measuring the value of universe acceleration H0 = 70.0+12.0 −8.0 kms−1 Mpc−1. Another event in this series GW190817 is Compact Binary Coalescence involving a 22.2 – 24.3 The EM counterpart of this event is unknown so far and hence the event is named Dark Siren.The Hubble’s value proposed with this even is close to H0 = 75+59 −13 km s−1Mpc−1 .The source GW190814 which involves a massive black hole and the other compact object as the lightest black hole or the heaviest neutron star was localized to 18.5 deg2 at a distance of Mpc.
poster number: 6.11 | zenodo
Samaporn Tinyanont
(University of California, Santa Cruz)
Ryan Ridden-Harper (JHU), Ryan Foley (UCSC), Viktoriya Morozova (Penn State), Charlie Kilpatrick (Northwestern), Georgios Dimitriadis (Trinity College Dublin), Armin Rest (STScI), Wynn Jacobson-Galan (Northwestern), Tony Piro (Carnegie), Mansi Kasliwal (Calech), Kishalay De (Caltech)
We will discuss joint early-time observations from TESS and HST, probing the close-in circumstellar environment of SN 2020fqv - a nearby hydrogen-rich core-collapse supernova (CCSN). Leading up to a CCSN, massive stars like the progenitor of SN 2020fqv can undergo significant mass loss and create a circumstellar medium (CSM). After the explosion, the SN shock crashes into the CSM converting some kinetic energy into light, causing the SN to brighten faster than it would otherwise. Thus, observing this early evolution of the SN can give valuable insights into the final stages of mass loss. The exquisite high cadence lightcurve of TESS, captures the rise of SN 2020fqv allowing us to precisely determine the explosion time and model the progenitor star, along with the surrounding CSM. We also triggered our ultra-rapid target-of-opportunity program with HST to obtain very early-time ultraviolet (UV) spectra of this SN, which showed spectroscopic signatures of CSM interactions. This joint analysis of data from TESS, and HST provides more evidence that the final years of red supergiant can be dramatic, and that early observations like those provided by TESS are key to understanding the CSM surrounding CCSNe.
poster number: 6.12 | zenodo
Andras Pal
(Konkoly Observatory)
Csaba Kiss, Robert Szakats (Konkoly Observatory)
Mainly, TESS observes an average minor planet with a quite decent apparent proper motion around a pixel or a fraction of a pixel per long cadence. However, some of the full frame images exhibit extraordinary long streaks corresponding to nearby objects with an apparent speed in the order of several minutes of arc per minute. Therefore, the parent objects of these streaks are usually visible only for a few frames. On the other hand, thanks to the on-board cosmic ray mitigation algorithm employed by the image acquisition electronics, these streaks are chopped into smaller segments, allowing us to determine its properties within a cadence of 20 seconds. All in all, we can say that despite the comparatively small number of frames, hundreds of individual data points are available for further analysis - allowing us to determine their physical characteristics and orbit. In this poster we exhibit few such objects and we try to answer the implied questions: who they are and where they go? Are these natural objects or artificial ones? Are these previously known or unknown ones?
poster number: 6.14 | zenodo
Tony L Farnham
(University of Maryland)
We are using the TESS full frame images to perform a survey of comets that serendipitously pass through the spacecraft's field of view. By monitoring the comets' short- and long-term temporal behavior, we can track secular changes in activity, measure the nucleus spin state and any changes in that state over time, map and analyze variability in the coma morphology, and search for spontaneous outbursts. TESS' instrumental stability, sampling cadence and long-duration observation baseline produce a dataset of unprecedented quality for this study, which has the potential to constrain the characteristics of more than 100 comets in various families. The data are especially useful for identifying rotation periods longer than 24 hours, which are under-sampled in ground-based observations, and for capturing the onset and early stages of outbursts, which have previously only been recorded on two occasions. By aligning and co-adding numerous images, we can also search for dust trails that will constrain the comets' dust properties and total mass loss rates. For specific high-profile comets, including potential spacecraft targets, we perform more detailed analyses to better characterize the activity for planning any future missions.
poster number: 6.16 | zenodo
Alexander Kosovichev
(New Jersey Institute of Technology)
Irina Kitiashvili (NASA Ames Research Center)
Precision asteroseismology data from Kepler and TESS provide a unique opportunity to investigate the interior structure of stars at various stages of stellar evolution. Detection of mixed acoustic-gravity oscillation modes has opened perspectives for probing properties of energy-generating cores. Most of the previous analysis was focused on fitting standard evolutionary stellar models using mode frequency splitting and scaling laws for oscillation properties. We present direct asteroseismic inversions using the method of optimally localized averages, which effectively eliminates the surface effects and attempts to resolve the stellar core structure.
poster number: 6.17 | zenodo
Aliz Derekas
(ELTE Eotvos Lorand University, Gothard Astrophysical Observatory, Szombathely, Hungary)
A. Derekas (ELTE Eotvos Lorand University, Gothard Astrophysical Observatory, Szombathely, Hungary; MTA-ELTE Exoplanet Research Group, 9700 Szombathely, Szent Imre h. u. 112, Hungary)
G. Hajdu (Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716, Warsaw, Poland)
A. Bokon (Department of Experimental Physics, University of Szeged, H-6720 Szeged, Dom ter 9, Hungary)
A.Bodi (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eotvos Lorand Research Network (ELKH), Konkoly Thege
Miklos ut 15-17, H-1121 Budapest, Hungary; MTA CSFK Lendulet Near-Field Cosmology Research Group, 1121, Budapest, Konkoly Thege Miklós út 15-17, Hungary)
I. B. Thompson (The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA)
A. Pal (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eotvos Lorand Research Network (ELKH), Konkoly Thege
Miklos ut 15-17, H-1121 Budapest, Hungary)
L.L. Kiss (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Eotvos Lorand Research Network (ELKH), Konkoly Thege
Miklos ut 15-17, H-1121 Budapest, Hungary; ELTE Eötvös Loránd University, Institute of Physics, Pazmany Peter setany 1/A, 1117 Budapest, Hungary; Sydney Institute for Astronomy, School of Physics A29, University of Sydney, NSW 2006, Australia)
M. Skarka (Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic; Astronomical Institute, Czech Academy of Sciences, Fricova 298, 25165, Ondrejov, Czech Republic)
BE Dor is a 15th magnitude first-overtone RR Lyrae variable star in the foreground of the Large Magellanic Cloud, located at about 8.7+/-3.3 kpc from the Sun. Previous investigations have revealed a cyclic period modulation with a period of 8 yr that is associated with a very stable light curve shape. To review and update our knowledge of the seemingly pure phase modulation, we collected all photometric data from the literature and extracted the light curves from all TESS Full Frame Image observations of the star. We extend the time base of earlier studies with another ~10 yrs, supplemented with new spectroscopic observations, and uncover further hints on the true physical nature of this intriguing pulsating star.
poster number: 6.19 | zenodo
Ayush Moharana
(Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences)
A. Moharana (1), K.G. Hełminiak (1), F. Marcadon (1), T. Pawar (1), M. Konacki (2)
(1) Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Rabianska 8, 87-100 Torun, Poland
(2) Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warszawa, Poland
Tight Triple Systems (TTS) have stars in a hierarchical configuration with a third star orbiting the inner binary with a period of fewer than 1000 days. Such systems are a hub of various dynamical interactions and are important for understanding the formation and evolution of stars in multiple systems. Having a detached eclipsing binary (DEB) as one of its components allows us to obtain precise stellar and orbital parameters of these systems. Various recent discoveries have been due to space-based photometry from Kepler and TESS. We present the accurate stellar and orbital parameters of a TTS, TIC 284595199, using TESS photometry coupled with radial velocities extracted from the triple-lined (SB3) spectra from HIDES spectrograph . Using these accurate parameters we determine the evolutionary states of the stars and the dynamic interactions possible in this system.
poster number: 6.20 | zenodo
Barbara Matécsa
(Eötvös Loránd University Department of Astronomy)
Tamás Hajdu (Konkoly Observatory, ELKH), Attila Bódi (Konkoly Observatory, ELKH)
We report the result of a search for CoRoT eclipsing binaries (EBs), which eclipse timing variation (ETV) shows the sign of potential light-travel time effect. To reveal their true nature, we needed longer time scales, thus we complement the CoRoT data with TESS measurements. Of about 2300 EBs, we focus our investigation on those systems, which were observed more than once both by CoRoT and TESS (in sectors 6 and 33), separately. We recalculated all of the orbital periods using phase dispersion minimization method, then produced the O-C diagrams. Finally, we analyzed those systems in details that showed sinusoidal ETVs with Markov chain Monte Carlo method. As a result we found 3 new hierarchical triple stellar system candidates.
poster number: 6.21 | zenodo
Catherine Clark
(Northern Arizona University/Lowell Observatory)
Gerard van Belle + Lowell Observatory, David Ciardi + NExScI Caltech/IPAC, Steve Howell + NASA Ames Research Center, Mark Everett + NOIRLab, Michael Lund + NExSCI Caltech/IPAC, Elliott Horch + Southern Connecticut State University
TESS has proven to be a powerful resource for uncovering planets, and the M-dwarfs have been established as favorable planet hosts. It has also become apparent that stellar multiplicity has wide-ranging implications for exoplanet detection and characterization, and that speckle imaging is one of the most efficient tools for probing these multi-star systems. We therefore present high-resolution imaging observations of 63 M-dwarfs using speckle cameras at the 3.5-m WIYN telescope, the 4.3-m Lowell Discovery Telescope, and the twin 8.1-m Gemini North and South telescopes. However, only one companion was detected. This finding is in contrast to the established 46% binarity rate in exoplanet host stars and the established 27% stellar multiplicity rate for field M-dwarfs. These results indicate that M-dwarf TOIs have a much lower multiplicity rate than field M-dwarfs. Our observations also imply that planet signals detected from M-dwarf TOIs are more likely to be real than those from higher-mass stars. Finally, these data support the observation that exoplanet-hosting binary stars have, in general, wider separations than field binaries.
poster number: 6.22 | zenodo
Christopher Lindsay
(Yale University)
Sarbani Basu (Yale University), Joel Ong (Yale University)
Most red giant models do not reproduce the position of the observed luminosity bump, a diagnostic of the maximum extension of the convective envelope during the first-dredge up. Global seismic parameters, the large frequency separation and frequency of maximum oscillation, show that overshoot below the convective envelope helps match red giant model luminosity bump positions to observed bump positions. The global seismic properties, however, cannot be used to probe envelope overshoot in a star-by-star manner. The long time series of Kepler and the TESS continuous viewing zones allow us to determine the individual mode frequencies of many red giants and these individual modes allow us to probe the internal structure of the stars. Red giant mixed modes (modes that are p-like at the surface and g-like in the core) contain important information about the interior structure of the star. We present the results of a theoretical study to investigate the seismic signature of convective overshoot in red giants. Our intention is to use these signatures to determine the amount of overshoot needed to model observed frequencies in red giants that have high quality seismic data.
poster number: 6.23 | zenodo
Daria Mokrytska
(Heidelberg Institute for Theoretical Studies)
S. Hekker (Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, Germany; Zentrum für Astronomie der Universtät Heidelberg, Landessternwarte, Königstuhl 12, D-69117, Heidelberg, Germany)
E. P. Bellinger (Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C,Denmark)
F. Ahlborn (Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1 ,85748 Garching, Germany)
Rotation is a physical phenomenon that impacts on the stellar structure and evolution of stars. Despite its importance, rotation in stars is not fully understood. In fact, predicted and observed rotation rates differ by more than an order of magnitude.
This difference between observations and models is highly pronounced in red-giant stars. In these stars waves exhibit sensitivity to both the core and the surface, allowing us to infer the radial differential rotation at the core and surface of these stars through so-called rotational inversions. To do so, we need an appropriate model of the star. Given the number of free parameters and one-dimensionality of the models, there is some degeneracy. Hence, models with different parameters could be identified as, or close to, the best-fitting model for a particular star. In this work we investigate how robust the rotation results from rotational inversions are to changes in stellar parameters of the models used.
poster number: 6.24 | zenodo
David Wilson
(UT Austin)
Boris Gaensicke (University of Warwick), JJ Hermes (Boston University), Jeremy Drake (SAO), Odette Toloza (University of Warwick).
Recent discoveries have demonstrated that planetary systems routinely survive the post-main-sequence evolution of their host stars, leaving the resulting white dwarf with a rich circumstellar environment. Among the most intriguing is the hot white dwarf GD 394, exhibiting a unique 1.150 ± 0.003 day flux variation detected in Extreme Ultraviolet Explorer observations in the mid-1990s. The variation has eluded a satisfactory explanation, but hypotheses include channelled accretion producing a dark spot of metals, occultation by a gas cloud from an evaporating planet, or heating from a flux tube produced by an orbiting iron-cored planetesimal. We present TESS observations of GD 394 demonstrating a 0.12 ± 0.01% flux variation with a period of 1.146 ± 0.001 days, consistent with the EUVE period and the first re-detection of the flux variation outside of the extreme ultraviolet. We describe the multi-wavelength observational history of GD 394, including HST, TESS and Chandra data, and discuss the implications of our results for the various physical explanations put forward for the variability of GD 394 and the opportunities to discover more GD394-like white dwarfs with TESS in the future.
poster number: 7.02 | zenodo
Dominick Rowan
(The Ohio State University)
Stanek, K. Jayasinghe, T. Kochanek, C.S., Thompson, T .A. (OSU)
Shappee, B. University of Hawaii Institute for Astronomy
Holoein, T. W. -S. Carnegie Observatories
Prieto, J. L. Universidad Diego Portales
The majority of non-merging stellar mass black holes are discovered by observing high energy emission from accretion processes. These interacting systems have masses of 5—10 Msun with a low mass gap from ~ 2—5 Msun that separates the neutron stars and stellar mass black hole populations. Since only a small fraction of potential binary configurations are expected to result in an interacting system, we aim to identify non-interacting black holes by searching for the tidally-induced ellipsoidal variability of their stellar companions. We start from a sample of about 200,000 rotational variables, semi-regular variables, and eclipsing binary stars from the All-Sky Automated Survey for Supernova (ASAS-SN). We use a χ^2 ratio test followed by visual inspection of TESS and ASAS-SN light curves to identify 379 candidates for ellipsoidal variability. We then combine the amplitude of the variability with mass and radius estimates for observed stars to calculate a minimum companion mass and identify the most promising candidates for high mass companions.
poster number: 7.03 | zenodo
Eleonora Fiorellino
(Konkoly Observatory - ELKH)
G Zsidi(1), Agnes Kospal(1, 2, 3), P. Abraham(1, 3)
1) Konkoly Observatory, ELKH
2) Max Planck Institute for Astronomy
3) ELTE Eotvos Lorand University, Institute of Physics
According to the magnetospheric accretion model, the mass accretion rate not only regulates the final stellar mass build-up, but also the evolution of the protoplanetary disk, determining the initial conditions for planet formation. In particular, the mechanism driving the evolution of disks is responsible for the transport of material through the disk onto the central star. For binary or multiple systems this scenario is complicated by the interplay of the stellar components, their disks, and the eventual presence of a circumbinary disk. For this reason, studying the accretion rates in multiple systems is of paramount importance to understand how the disk evolves. The multiple system WX Cha, composed of three young stellar objects, is one of the best candidates to investigate the accretion rates to study how the photometric variability is related to the accretion process. We obtained high resolution optical spectra of the WX system with ESPRESSO and FEROS at seven different epochs over three months. We analyzed the spectra together with contemporaneous TESS photometry. We estimated the accretion luminosity from the HI lines, and computed the stellar properties of the system, providing the mass accretion rate for each epoch.
poster number: 7.04 | zenodo
Emese Plachy
(Konkoly Observatory CSFK)
Attila Bódi (Konkoly Observatory CSFK)
András Pál (Konkoly Observatory CSFK)
László Molnár (Konkoly Observatory CSFK)
László Szabados (Konkoly Observatory CSFK)
TESS has a significant advantage in variable star classification over all-sky surveys that work with sparsely sampled photometric data. Beyond the classical problem of misidentified eclipsing and rotational variables among the pulsating stars, confusion between Cepheid types also exists. Here we focus on the anomalous Cepheid type of stars that lie in between Type I and II Cepheids regarding masses and luminosities. They represent the most metal poor and the least numerous type of Cepheids, for which evolutionary channels are a matter of debate. Their observed pulsation periods range between 0.3 to 2.7 days overlapping with the other Cepheids types and RR Lyrae stars, and their light curve shapes are very similar to each other. Photometric data alone are often not adequate to distinguish them, therefore only a handful of variable catalogs list anomalous Cepheids as an independent type. In this study we explore the potential of TESS in the validation of anomalous Cepheid candidates by investigating full-frame image light curves prepared with our differential photometric pipeline.
poster number: 7.05 | zenodo
Eric Jensen
(Swarthmore College)
Celia Parts, Swarthmore College; Ann Sinclair, Swarthmore College; Karen Collins, Harvard-Smithsonian Center for Astrophysics; John Kielkopf, Univ. of Louisville; Kim McLeod, Wellesley College
Mass is one of the most fundamental stellar parameters, arguably exerting more influence on a star's evolution than any other single variable. Accurate and precise stellar masses play an essential role in constraining models of pre-main-sequence stellar evolution, where existing sets of models can differ significantly in mapping observed luminosity and effective temperature to an inferred age and mass for a given star. To determine which models are correct, directly measured masses of more young stars are needed. We present the method and results of our focused search for young eclipsing binaries using TESS full-frame images (FFIs). We examine the FFI lightcurves of known young stars that show radial velocity variations in APOGEE data, focusing in particular on those found to show evidence of being double-lined. The accurate stellar masses and radii determined from any targets that are found to be double-lined eclipsing binaries will provide valuable constraints on evolutionary models.
poster number: 7.06 | zenodo
Ethan Kruse
(NASA Goddard)
Brian Powell, NASA Goddard
Veselin Kostov, NASA Goddard
Jeremy Schnittman, NASA Goddard
Elisa Quintana, NASA Goddard
We have created over 60 million light curves from the TESS full frame images using a local implementation of the eleanor pipeline: a light curve for nearly every star brighter than 15th magnitude in the 26 TESS prime mission sectors. With this unprecedented set of light curves, we have developed a machine learning classification tool to identify classes of variable stars. Here I will focus on the ~300,000 eclipsing binaries identified via this machine learning classifier. I will present the overall sample, discuss our filters and sensitivity limits, and show how we have uniformly modeled them all. I will also present preliminary population results as well as highlight unique discoveries in unusual regions of parameter space.
poster number: 7.07 | zenodo
Ewa Niemczura
(University of Wroclaw)
Barry Smalley (Keele University), Simon J. Murphy (The University of Sydney)
The metallic-line (Am) stars are chemically peculiar A and early F stars that show weak spectral lines of Ca K and Sc and strong iron-group features compared to their hydrogen-line spectral type. The abundance peculiarities of Am stars can be explained by chemical separation due to radiative diffusion and gravitational settling. In a normal A star this separation is destroyed by fast rotation, however Am stars rotate slowly enough to prevent this mechanism. The metallic-line stars are located in the classical instability zone, where pulsating Delta Scuti stars lie. The Delta Scuti pulsations are driven by the kappa-mechanism operating in the He II ionisation zone. For many years it was assumed that classical Am stars cannot pulsate due to the gravitational settling of helium. However, over time it appeared that many Am stars pulsate. We analyse high-precision photometric data gathered by the TESS satellite to check (1) if pulsation characteristics (e.g. number of frequencies, amplitudes) are different for Am and chemically normal stars, and (2) if the incidence of pulsations in Am stars decreases with increasing degree of chemical peculiarity.
poster number: 7.08 | zenodo
Gabriella Zsidi
(Konkoly Observatory; Eötvös Loránd University)
Eleonora Fiorellino (Konkoly Observatory)
Ágnes Kóspál (Konkoly Observatory; Eötvös Loránd University,Institute of Physics)
Péter Ábrahám (Konkoly Observatory; Eötvös Loránd University,Institute of Physics)
Young stellar objects are surrounded by a circumstellar disk, from which material is falling onto the stellar surface. According to the magnetospheric accretion model, the stellar magnetic field truncates the disk at the distance of a few stellar radii and channels the disk material onto the star. Although usually described with simple and static models, this accretion process is inherently time variable, therefore our aim is to characterize the accretion process in time and study the accretion diagnostic parameters. Here, we present a complex study of VW Cha, a low-mass young star. We combined the TESS observations with contemporaneous ground-based IJHK-band photometry, and multi-epoch optical spectroscopic observations obtained by the VLT/ESPRESSO and the 2.2m/FEROS spectrographs. Besides uncovering the periodic light variations that can be attributed to the stellar rotation, the uninterrupted TESS observations allow us to examine the shorter timescale fluctuations probably due to accretion variability. Using the additional observations, we identify accretion tracers and study where they form, measure the accretion rate, and determine the distribution and the kinematics of the accreting material.
poster number: 7.09 | zenodo
Gavin Ramsay
(Armagh Observatory & Planetarium)
Dmitrii Kolotkov (U Warwick, Institute of Solar-Terrestrial Physics Irkutsk), J Gerry Doyle (Armagh), Lauren Doyle (U Warwick)
We have performed a search for flares and Quasi-Periodic Pulsations (QPPs) from low mass M dwarfs using TESS 2 min cadence data. We find seven stars which show evidence of QPPs. We confirm the presence of 11 QPPs in these seven stars with a period between 10.2 and 71.9 min, including an oscillation with drift in the period and a double-mode oscillation. The fraction of flares we examined which showed QPPs (7 percent) is higher than other studies of stellar flares, but is very similar to the fraction of Solar C-class flares. We determine the length of the coronal loops using several approaches and find they are similar to the stellar radius or greater. We also discuss the flare frequency of the seven stars determining whether this could result in ozone depletion or abiogenesis. Two of our stars have a sufficiently high rate of energetic flares which are likely to cause abiogenesis, while four of them are in the range for ozone depletion to occur. We speculate on the implications for surface life on these stars and the effects of the loop lengths and QPPs on potential exoplanets in the habitable zone.
poster number: 7.10 | zenodo
Guadalupe Tovar Mendoza
(University of Washington)
James R.A. Davenport (University of Washington), Suzanne L. Hawley (University of Washington)
Stellar variability is a limiting factor for planet detection and characterization, particularly around active stars. By understanding the light curve profile of flares on active M-dwarfs we can help improve exoplanet detection and characterization. Here we revisit one of the most active stars from the Kepler mission, the M4 dwarf GJ 1243, and use a sample of 303 stellar flares from 11 months of 1-minute cadence light curves to study the empirical morphology of stellar flares. We use a Gaussian process detrending technique to account for the underlying starspots. We present an improved analytic, continuous flare template that is generated by stacking the flares in a scaled time and amplitude and using Markov Chain Monte Carlo to fit the model. Our model is defined using classical flare events, but can also be used to model complex, multi-peaked flare events. We test our model using TESS data at both the 2-minute and 20-second cadence modes, showing the general utility of our empirical flare template.
poster number: 7.11 | zenodo
Hiroyuki Maehara
(National Astronomical Observatory of Japan)
Notsu, Yuta (University of Colorado Boulder); Namekata, Kousuke (NAOJ); Honda, Satoshi (University of Hyogo); Kowalski, Adam F. (University of Colorado Boulder); Katoh, Noriyuki (University of Hyogo); Ohshima, Tomohito (University of Hyogo); Iida, Kota (Tokyo Institute of Technology); Oeda, Motoki (Tokyo Institute of Technology); Murata, Katsuhiro L. (Tokyo Institute of Technology); Yamanaka, Masayuki (Kyoto University); Takagi, Kengo (Hiroshima University); Sasada, Mahito (Hiroshima University); Akitaya, Hiroshi (Chiba Institute of Technology); Ikuta, Kai (Kyoto University); Okamoto, Soshi (Kyoto University); Nogami, Daisaku (Kyoto University); Shibata, Kazunari (Kyoto University)
We report the results from spectroscopic and photometric observations of the M-type flare star YZ CMi in the framework of the Optical and Infrared Synergetic Telescopes for Education and Research (OISTER) collaborations during the Transiting Exoplanet Survey Satellite (TESS) observation period. We detected 4 H-alpha flares and one of them did not show clear brightening in the continuum; during this flare, the H-alpha line exhibited blue-asymmetry which has lasted for ~ 60 min. The line of sight velocity of the blue-shifted component is ~ -80 km/s. Under the assumption of that observed blue-asymmetry in H-alpha line was caused by a prominence eruption, the mass and kinetic energy of the upward-moving material are estimated to be 10^{16} - 10^{18} g and 10^{29.5} - 10^{31.5} erg, respectively. Although the estimated mass is comparable to expectations from the empirical relation between the X-rat flare energy and mass of solar coronal mass ejections (CMEs), the estimated kinetic energy is roughly 2 orders of magnitude smaller than that expected from the relation for solar CMEs. This discrepancy could be understood by the difference in the velocity between CMEs and prominence eruptions (Maehara et al. 2021 PASJ, 73, 44).
poster number: 7.12 | zenodo
Irina N Kitiashvili
(NASA Ames Research Center)
Alan A Wray
A dramatic increase in observational data from NASA’s Kepler, K2, and TESS missions and supporting ground-based observatories have opened new opportunities to investigate the internal structure, dynamics, and evolution of stars and their atmospheres. We present 3D radiative MHD simulations for several main-sequence stars with masses from 1.4 to 1.5 Msun and different metallicities. The simulations are performed using the "StellarBox" code developed for modeling stellar turbulent convection and atmospheres with a high degree of realism. This presentation discusses similarities and differences between 3D realistic-type and 1D mixing-length models, structural, thermodynamical, and turbulent properties variations from the radiative zone to the convection zone and photosphere. Also, we discuss how 3D stellar properties affect asteroseismic characteristics.
poster number: 7.13 | zenodo
Jacob A Kosowski
(Heidelberg Institute for Theoretical Studies)
As low mass stars (< 2.3 Msol) ascend the red-giant branch, they experience a brief period of contraction, paired with decreasing luminosity and increasing effective temperature, known as the red-giant branch bump. This period ends when the hydrogen-burning shell surpasses the mean-molecular weight discontinuity. The effects of the star's initial parameters on the behavior of the bump is not fully understood. I used MESA to model a grid of stars, varying in mass and metallicity, in order to provide insight into the inner workings of red-giants during this evolutionary period and to compare the bump across a range of initial stellar parameters. Analysis of the MESA data shows possible relationships between a star’s initial parameters and the state of its internal structure during the period of the bump. These relationships may provide insight into the mechanisms that govern the bump and its effect on the evolution of these low-mass stars.
poster number: 7.14 | zenodo
Jérôme Bétrisey
(Université de Genève)
Gaël Buldgen, Université de Genève
In the last decade, astonishing progresses were achieved in asteroseismology thanks to the revolution initiated by the high-quality data from the space-based missions CoRoT, Kepler and TESS and continued with the future PLATO mission. This high precision is however limited by the “so-called” surface effects of solar-like oscillations. Indeed, despite several attempts (Kjeldsen et al. 2008, Ball et al. 2014, Sonoi et al. 2015, Ball et al. 2016), current approaches remain empirical and constitute a weakness in stellar modelling and inversion techniques. As illustrated in Buldgen et al. (2019) and Bétrisey et al. (submitted), their actual implementation shows biases on the estimated stellar parameters. For this reason, we developed a new indicator and based on the inversion of frequencies ratios instead of individual frequencies as it is currently done. This approach is motivated by the works of Roxburgh & Voronsov (2003) and Oti Floranès et al. (2005) who pointed out that these frequencies ratios and their corresponding kernels are not sensitive to surface regions. In contrast, they are sensitive to deeper stellar layers. Therefore, our new indicator seems promising to better probe central stellar regions of intermediate-mass stars
poster number: 7.15 | zenodo
Jiaxin Tang
(Tsinghua Uninversity)
Sharon Xuesong Wang, Tsinghua Unniversity; RVxTESS Team
The Radial Velocity (RV) method is widely used for the study of exoplanets. For low-mass planets, RV detection typically requires cm/s precision, whereas the stellar jitter becomes an issue at the m/s level. Thus, it is essential to mitigate it in order to detect Earth-like planets. Our project focuses on the asteroseismic signals including stellar oscillation and granulation. We study HD 5562 with fitting the model of stellar jitter to the observational data from TESS and Magellan/PFS. HD 5562 is a G-type subgiant (M=0.93M⨀, V=7.16mag, L=2.3L⨀). We conduct a Gaussian Process (GP) regression on the star's photometric and RV data to describe the stellar jitter. Our new model suggests that the primary mode of its oscillation is around 15 minutes, shorter than the prediction of 44 minutes derived from its mass and luminosity. The periodogram suggests that granulation has a stronger signal than oscillation in the light curve. Our RV fit will be aided by the GP regression of the light curve. Our project is part of the RVxTESS program (RVxTESS.com), which combines simultaneous TESS photometry with ground-based RV observations to study stellar jitter.
poster number: 7.16 | zenodo
Jonathan Labadie-Bartz
(University of Sao Paulo)
Alex Carciofi - University of Sao Paulo
Classical Be stars are near-critical rotators which occasionally eject mass and angular momentum to form circumstellar 'decretion' disks. Space photometry has revealed that Be stars are pulsators as a rule, and evidence is mounting that pulsation plays a role in the mass ejection mechanism. This poster will provide a summary of a study of the TESS light curves for ~500 Be stars. Virtually all Be stars are variable, with the vast majority showing `frequency groups' (which represent multi-mode pulsation). About 20% of the sample shows brightening events that reflect mass ejection episodes, often with associated enhancements in the strength of the frequency groups. In some stars, there is evidence of non-linear coupling of individual pulsation modes which can control the timing of mass outbursts. Time-series spectroscopy simultaneous with the TESS observations for selected targets provides crucial information for interpreting the photometric variability. Correlations between different variability patterns are studied to better understand the overall behavior of the Be star population.
poster number: 7.17 | zenodo
Joyce Ann Guzik
(Los Alamos National Laboratory)
Joyce Ann Guzik (Los Alamos National Laboratory, Los Alamos, NM USA), Jason Jackiewicz (New Mexico State University, Las Cruces, NM USA), Giovanni Catanzaro (INAF--Osservatorio Astrofisico di Catania, Catania, Italy), Michael S. Soukup (Albuquerque, NM, USA)
Metallic-line A (Am) stars are main-sequence stars of around twice the mass of the Sun that show element abundance peculiarities in their spectra. The radiative levitation and diffusive settling processes responsible for these abundance anomalies should also deplete helium from the region of the envelope that drives delta Scuti p-mode pulsations via the kappa (opacity) mechanism. Therefore, these stars are not expected to pulsate in multiple radial and nonradial modes with periods of around 2 hours, characteristic of delta Scuti stars. As part of the TESS Guest Investigator programs Cycles 2 and 3, we proposed observations in 2-minute cadence of bright (visual magnitudes 7-8) Am stars. As of March 2021, 55 target stars have been observed; among them we find four delta Scuti stars and four delta Scuti/gamma Doradus hybrid candidates, as well as many stars showing variability possibly caused by rotation and starspots. Confirming the pulsations will require further analysis and follow-up, including ruling out contamination from background or nearby stars in the field. Asteroseismic modeling of these stars will be useful to understand the reasons for their pulsations and the connections to their abundance peculiarities.
poster number: 7.18 | zenodo
Kai Ikuta (Kyoto University)
(Kyoto University)
Hiroyuki, Maehara (NAOJ), Yuta Notsu (University of Colorado Boulder/National Solar Observatory/Tokyo Tech), Kosuke Namekata (NAOJ), Taichi Kato, Soshi Okamoto (Kyoto University), Shota Notsu (RIKEN), Satoshi Honda (University of Hyogo), Daisaku Nogami, Kazunari Shibata (Kyoto University)
We implemented a code to decipher stellar surface information from Kepler/TESS light curves specified by many stellar/spot parameters with a parallel tempering (Ikuta et al. 2020) because it has been suggested that there are many spots on the surface. The code enables to deduce parameters, such as the spot location, size, emergence/decay rates, and the stellar differential rotation, and to calculate the model evidence in the Bayesian framework. We show degeneracies between all the parameters and the comparison of the number of spots by revisiting synthetic light curves emulating Kepler/TESS data. Then, we applied the code to TESS light curves of M-dwarf flare stars, AU Mic, EV Lac, and YZ CMi (Ikuta et al. 2021, to be submitted). As results, the spot location and size are uniquely deduced and almost consistent with those in other studies; the spot location is suggested to be uncorrelated with flares in the light curve; the variation of the light curve structure for AU Mic and YZ CMi in two TESS Cycles can be explained by the stellar differential rotation or spot emergence/decay. We also verify the validity of starspot mapping and propose other approaches to resolve the conundrum.
poster number: 7.19 | zenodo
Kamil Bicz
(Astronomical Institute of the University of Wrocław)
Since the release of the first TESS sector the possibility of examining stellar flares and stellar dynamo compared to the solar dynamo and solar flares has increased. Thanks to this observations we tried to estimate staining of low mass stars with visible variability of their luminosity. We managed to do this using newly created software called BASSMAN (Best rAndom StarSpots Model calculAtioN) that allows to estimate amount of spots on star and parameters of the estimated spots. Trying to recreate spots on star can help examine more deeply how inner structure of the star can be connected to staining of star, how the spots evolve or appear on the star or how spots are related to flares. Here I will present results of modelling of star spots for 2 stars with our new tool and compare the results with the previous reconstructions of the spatial distribution of spots.
poster number: 7.20 | zenodo
László Molnár
(Konkoly Observatory, CSFK)
Attila Bódi (Konkoly Observatory, CSFK), András Pál (Konkoly Observatory, CSFK), and TASC WG#6 members
TESS and Gaia are both collecting data of exquisite quality for RR Lyrae-type pulsating stars. We combine light curve shape information from TESS with distances and brightnesses from Gaia to build a detailed classification scheme that is able to filter out intrinsically fainter binaries and rotational variables as well as short-period Cepheids that have light curves very similar to that of RR Lyrae stars, while preserving targets with unusual light curves. We build a clean sample from the vicinity of the Sun, out to 5-10 kpc distances. Based on the TESS light curves we find that a large fraction of RR Lyrae stars exhibit various additional low-amplitude modes. The distribution of extra modes in period is markedly different from that of stars within the bulge and globular clusters, signaling a metallicity dependence in the mode periods and excitation mechanisms. We also detect a possible dependence of extra modes from color and hence effective temperatures in overtone RRc stars. While these new results have brought us closer to true asteroseismic analysis of RR Lyrae stars, we show through new echelle-type diagrams that mode identification is still hindered by the strong influence of the radial mode(s) dominating the pulsation.
poster number: 7.21 | zenodo
Laura D. Vega
(NASA GSFC / UMD)
Patricia T. Boyd (NASA GSFC),
Thomas Barclay (NASA GSFC, UMBC),
Joshua E. Schlieder (NASA GSFC),
Elisa V. Quintana (NASA GSFC),
Rishi R. Paudel (NASA GSFC, UMBC),
Emily A. Gilbert (NASA GSFC, University of Chicago),
Jacqueline R. Villadsen (St. Mary's College of Maryland),
Michele Silverstein (NASA GSFC, USRA),
Teresa A. Monsue (NASA GSFC, USRA),
Allison Youngblood (NASA GSFC),
Knicole Colon (NASA GSFC), and
Keivan G. Stassun (Vanderbilt University)
The relatively young and highly active M dwarf star, YZ CMi, was simultaneously observed by the Transiting Exoplanet Survey Satellite (TESS), the Neil Gehrels Swift Observatory (Swift), and the Very Large Array (VLA) in 2019 January. An extreme flaring event (>24 minutes, ~7.6x10^31 erg) occurred on 2019 January 25 that was detected by all three observatories. TESS re-observed YZ CMi in 2021 January, this time at 20-second cadence, which allowed the detection of smaller flares and better resolved flare morphology in white light as compared to the 2-minute data collection mode. We compare flare rates between both TESS observation periods and analyze the spot evolution in TESS Sectors 7 and 34, due to changes in brightness variability activity from the two different TESS sectors. Simultaneous observations were also taken with Swift, the Neutron Interior Composition Explorer (NICER), and the CTIO/SMARTS 0.9m during Sector 34. We analyze the energy partition of flares and compare the flare frequency distribution (FFDs) of events observed simultaneously by the different observatories.
poster number: 7.22 | zenodo
Laura Venuti
(SETI Institute)
Ann Marie Cody (SETI Institute), Luisa M. Rebull (IPAC/Caltech), Giacomo Beccari (ESO/Garching), Mike Irwin (Institute of Astronomy, Cambridge), Sowmya Thanvantri (UC Berkeley), Steve B. Howell (NASA Ames Research Center), Geert Barentsen (Bay Area Environmental Research Institute)
Space telescopes have provided unprecedented depictions of the manifold variability behaviors typical of young stellar objects (YSOs). However, the lack of coordinated, multiband data often limited our understanding of the observed flux patterns. We conducted a comprehensive variability survey of 278 B-to-K YSOs in the 1-2 Myr-old cluster NGC 6530. Our sample was monitored with Kepler/K2, and simultaneous u,g,r,i,Halpha time series were acquired with VST/OmegaCAM. We detected substantially lower variability on B/A stars than on G/K stars for any light curve morphology, and a dearth of some distinctive disk-driven behaviors among stars earlier than G. We could also pinpoint distinct contributions to the leading day-to-week variability timescales, from intense accretion triggered by inner disk instabilities, to variable accretion efficiency in the outer magnetosphere. On the heels of that project, we are undertaking a new survey of the Taurus star forming region, coupling high-precision photometry from TESS with simultaneous u,g,r,i data from the Las Cumbres Observatory. This program will provide unique constraints on the physical drivers of YSO variability, and on the mid- to long-term stability of inner disks around young stars.
poster number: 7.23 | zenodo
Lauren Doyle
(University of Warwick)
L. Doyle (Warwick), G. Ramsay (Armagh), S. Bagnulo (Armagh), J.G. Doyle (Armagh), P. Hakala (FINCA)
We identify a small group of low mass ultra fast rotating (UFR) stars which have rotation periods less than 0.3 days and show low levels of flaring activity in their TESS lightcurves. Given the rotation-activity relation, faster rotating stars should display higher levels of activity. We do not find any evidence that the lack of activity is related to age or rotational velocities and conclude it is most likely to be a result of the magnetic configurations of the star. In this talk, we will discuss the further analysis of these UFRs using TESS data from Cycles 1-3, NOT spectra and FORS2 spectropolarimetric observations. Overall, we compare the flare rates between the TESS Cycle lightcurves while investigating any long term variability. The NOT spectra is used to investigate radial velocity variations ruling out potential short duration binaries. We also bring in the spectropolarimetric data to determine an estimate on the magnetic field strength of our targets. If these objects do possess a strong magnetic field then why do they not show more flares? Also, If they do not possess a strong field then how can such rapidly rotating stars not show evidence for a magnetic field?
poster number: 8.01 | zenodo
Leila M Calcaferro
(IALP, CONICET-UNLP )
Alejandro H. Córsico (IALP, CONICET-UNLP), Leandro G. Althaus (IALP, CONICET-UNLP), Keaton J. Bell (DIRAC Institute, Department of Astronomy, UW)
While evolving toward their terminal white-dwarf cooling branches, some low-mass helium-core white dwarf stellar models experience a number of nuclear flashes. Just before the occurrence of each flash, stable hydrogen burning may be able to drive global pulsations that could shed some light on the internal structure of these stars through asteroseismology. In this work, we perform a pulsational stability analysis considering the effects of the ε mechanism in destabilizing gravity-mode periods for sequences of low-mass white dwarfs evolving through CNO flashes. We show that the ε mechanism due to stable hydrogen burning can excite low-order (ℓ=1,2) gravity modes with periods between ∼80 and 500 s, for stars with 0.2025≲M⋆/M⊙≲0.3630 located in an extended region of the logg−Teff diagram.
poster number: 8.02 | zenodo
Lisseth Gonzales
(Universidad Nacional Mayor de San Marcos)
Daniella Bardalez Gagliuffi (AMNH), Jacqueline Faherty (AMNH), Mark Poppinchalk (AMNH, CUNY Graduate Center), Jason Curtis (Columbia University, AMNH), Johanna Vos (AMNH), Andrew Ayala (AMNH)
Determining ages of stars is one of the most elusive tasks in Astrophysical studies. Stellar evolution is a slow process and is dependent upon the temperature and mass of a given object. Young associations near the Sun provide a unique opportunity to evaluate ages as well as age indicators. Examining the gyrochronology relation for young associations lets us probe how stellar rotation changes with mass as these groups of stars are born together, evolve together, and move through space as an ensemble. At 120±20 Myr, AB Doradus is one of closest moving groups to Earth, which allows us to obtain high signal-to-noise light curves for its stellar down to brown dwarf members. The all-sky TESS mission is ideal for observing a group like AB Doradus given the spatial extent of this moving group. In this poster, we present rotation periods for ~1200 confirmed and candidate members of AB Doradus across multiple TESS sectors to provide the first ever look at the gyrochronology relation for this association.
poster number: 8.03 | zenodo
Luisa Rebull
(Caltech-IPAC/IRSA)
Lynne Hillenbrand (Caltech), Ann Marie Cody (Bay Area Environmental Research Institute), John Stauffer (IPAC)
In recent years, we have been using K2's high precision photometry to probe stellar variability and stellar rotation to lower masses and lower amplitudes than has ever been done before. Younger stars are generally more rapidly rotating and have larger star spots than older stars of similar masses. K2's large field of view was able to monitor a significant fraction of many nearby clusters and associations; some of the nearest associations can only be monitored by TESS, which observes ~85% of the sky. We present rotation rates from a TESS study of stars in the ~15 Myr old Upper Centarus-Lupus (UCL)/Lower Centaurus-Crux (LCC) association.
poster number: 8.04 | zenodo
Madeline Howell
(Monash University)
Simon Campbell - Monash University
Asteroseismology provides a new avenue to study stellar evolution and globular cluster (GC) formation. Using photometry from the K2 mission, we have measured asteroseismic masses for 39 evolved stars in the GC M4, and found the integrated mass loss along the red giant branch and red horizontal branch. M4 remains the only GC for which it is possible to measure mass loss with the current available photometry. This study reports the largest ever seismic analysis of GC stars, and also the first detection of oscillations in early asymptotic giant branch stars in GCs. Interestingly, we discovered a weak bi-modal mass distribution along each branch. With future spectroscopic measurements, we aim to determine if the bi-modality reflects the multiple populations of M4. If the mass difference is confirmed to track the multiple populations, then this is strong independent evidence for the inferred He differences between populations. This He variation will correspond to different population ages, which supports the hypothesis that the sub-populations in a GC are different generations.
poster number: 8.05 | zenodo
Małgorzata Pietras
(University of Wrocław)
In my talk I will present a statistical study of stellar flares based on TESS observations. We used a two-minute cadence data obtained from sectors 1 - 35. Our software allows us to identify flares and determine its parameters such as: amplitude, duration, growth and decay times. Furthermore, we estimate the maximum luminosity and total energy of flares in two different methods. We investigate distributions of flare frequencies and its dependence upon spectral types. In the first two years of TESS observations, we already identified about 130 000 flares from more than 22 000 flaring stars from F-type to M-type. From the analysis we conclude that approximately 7.8 percent of all observed stars show flaring activity, which is in agreement with other papers on this topics. Based on bolometric flare energy distribution, we conclude that its energies range from 10^31 to 10^38 erg, with an average energy of 1034 erg. Our study suggests that there are two types of flare events, described by different profiles. The result of the performed analysis is also the statistical distribution of the parameters of flaring stars.
poster number: 8.06 | zenodo
MARCADON Frédéric
(Nicolaus Copernicus Astronomical Center)
F. Marcadon,1 K. G. Helminiak,1 J. P. Marques,2 R. Pawlaszek,1 P. Sybilski,1 S. K. Kozlowski,1 M. Ratajczak,3 M. Konacki,1
1, Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Rabianska 8, 87-100 Torun, Poland
2, Institut d'Astrophysique Spatiale, UMR8617, CNRS, Université Paris-Saclay, Bâtiment 121, 91405 Orsay Cedex, France
3, Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
We present a new analysis of the multiple star V1200 Centauri based on the most recent observations for this system. We used the photometric observations from the Solaris network and the TESS telescope, combined with the new radial velocities from the CHIRON spectrograph and those published in the literature. We confirmed that V1200 Cen consists of a 2.5-day eclipsing binary orbited by a third body. Regarding the third body, we obtained significantly different results than previously published. Indeed, we argue that V1200 Cen is a quadruple system with a secondary pair composed of two low-mass stars. We also determined the ages of each eclipsing component using two evolution codes, namely MESA and CESTAM. We obtained ages of 16-18.5 Myr and 5.5-7 Myr for the primary and the secondary, respectively. In particular, the secondary appears larger and hotter than predicted at the age of the primary. Finally, we concluded that dynamical and tidal interactions occurring in multiples may alter the stellar properties and explain the apparent non-coevality of V1200 Cen.
poster number: 8.07 | zenodo
Marek Skarka
(Astronomical Institute of the Czech Academy of Sciences)
Zbynek Henzl, Variable stars and exoplanet section of the Czech Astronomical Society
Reinhold Auer, Variable stars and exoplanet section of the Czech Astronomical Society
Jiri Liska, Variable stars and exoplanet section of the Czech Astronomical Society
Martin Masek, Variable stars and exoplanet section of the Czech Astronomical Society
David Stegner, Masaryk University, Brno, Czech Republic
The region of the main sequence where A and F stars are located is a transition region of various physical phenomena. This is the reason why we can observe stars showing signs of rotation, pulsation, chemical peculiarity, binarity, etc. often at the same time. To our current knowledge, some of the observed phenomena should not co-exist. We present the identification and classification of the A-F variable stars near the ecliptic pole gathered by the TESS satellite and show some intriguing cases.
poster number: 8.08 | zenodo
Markus Rabus
(Universidad Católica de la Santísima Concepción)
Theron Carmichael, CfA
Avi Shporer, MIT
Marshall Johnson, LCO
David W. Latham, CfA
Tim Brown, LCO
Karen Collins, CfA
Tianjun Gan, Tsinghua University
Allyson Bieryla, CfA
John Kielkopf, University of Louisville
Nicola Astudillo-Defru, Universidad Católica de la Santísima Concepción (UCSC)
Erica Gonzalez, University of California Santa Cruz
Coel Hellier, Keele University
Brett C. Addison, University of Southern Queensland
Andreea-Ioana Henriksen, Technical University of Denmark
Lars Buchhave, Technical University of Denmark
René Tronsgaard Rasmussen, Technical University of Denmark
Ben Fulton, IPAC
Steve B. Howell, NASA Ames
David Ciardi, Caltech/IPAC-NExScI
Amaury Triaud, University of Birmingham
We describe in the underlying investigation the discovery of two eclipsing binary systems. In both cases, the companions are most likely fully convective low-mass stars. The TESS team initially alerted the systems as TOI-1830 (TIC20182165, HD133725) and TOI-1312 (TIC405904232), and we subsequently observed them with spectroscopy. The TESS light curves and spectroscopic observations were analyzed in a combined data-driven framework to estimate the systems’ parameters. Radial velocity (RV) measurements with LCO/NRES, NOT/FIES, SONG, and TRES indicated for the TOI-1830 system a companion mass of 0.11 M☉ in a 9.781-day eccentric orbit and a 0.10 M☉ companion in an 11.080-day eccentric orbit for the TOI-1312 system. At the same time, the spectroscopic observations were used to estimate the spectral type of the main stars for TOI-1830 and TOI-1312. We measured the radii ratio from the TESS light curves and estimated the companions’ radii, assuming the main stars’ radii as measured from spectroscopy and isochrones. Given the youth of TOI-1830 and the evolved age of TOI-1312, both systems will provide valuable insights into the stellar evolution of close binary systems.
poster number: 8.09 | zenodo
Maryum Sayeed
(Institute for Astronomy, University of Hawai'i)
Daniel Huber (Institute for Astronomy, University of Hawai'i)
Asteroseismology is a powerful tool to probe stellar interiors and constrain fundamental stellar properties. Currently, the number of dwarfs and subgiants with solar-like oscillations is limited. To expand the sample, we re-analyze Kepler short-cadence data using pySYD, an automated pipeline to extract global asteroseismic parameters. We present 80 new detections in Kepler short-cadence data, increasing the currently known sample of dwarfs and subgiants with solar like oscillations by ~15%. We derive stellar mass and radius using scaling relations, and use TESS short-cadence data of the Kepler sample to study the dependence of oscillation amplitudes on wavelength. Our new detections greatly improve the sample of asteroseismic benchmark dwarfs and subgiants in Kepler data, and provide a glimpse of the discovery of solar-like oscillators with TESS. This increase in seismic detections will enable precise characterization of planetary systems, and provide new candidates to test gyrochronology models.
poster number: 8.10 | zenodo
Mathieu Vrard
(Ohio State University)
Vrard, M. (1) ; Pinsonneault, M. (1) ; Hon, M (2) ; Kuszlewicz, J. (3) ; Li, Y (4) ; Mackereth, J.T. (5) ; Miglio, A. (5) ; Hekker, S. (6) ; Mathur, S. (7) ; Stello, D (8) & Elsworth, Y. (5)
1: Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA
2: Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
3: Landessternwarte, Zentrum f¨ur Astronomie der Universit¨at Heidelberg, K¨onigstuhl 12, 69117, Heidelberg, Germany
4: Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia
5: School of Astronomy and Astrophysics, University of Birmingham,
Edgbaston, Birmimgham, B15 2TT, UK
6: Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
7: Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain
8: School of Physics, The University of New South Wales, Sydney NSW 2052, Australia
Since its launch in 2018, the TESS satellite has observed hundreds of thousands of stars. The longest stellar observations occurred in the South and North Continuous Viewing Zones (CVZ) where the light-curve lengths can go as far as one year. This length will allow us to perform precise seismology on those objects and use it to deduce precise stellar characteristics. In this talk we will present the first evolutionary status determination of red giant stars from the TESS South CVZ data. We used a sample of more than 5000 stars for which oscillations were already detected and the global seismic parameters already determined. We gathered the results of different evolutionary status determination techniques on these data and found a consensus for more than 2000 stars. The agreement between the different techniques was around 20%, much lower than for Kepler. We will discuss the cause behind this lower agreement and examine the adaptation that needs to be made to make those methods more suitable to TESS data. These results assess the possibility of determining the evolutionary status of red giant stars with TESS and pave the way for further red clump star identification which will be crucial to determine the age of stellar populations.
poster number: 8.11 | zenodo
Matthew Green
(Tel Aviv University)
Dan Maoz, Tel Aviv University
Tsevi Mazeh, Tel Aviv University
Simchon Faigler, Tel Aviv University
Binary systems with small orbital separations display photometric signatures that result from the tidal distortion of their component stars, as well as from Doppler beaming and from reflection. These signatures can be used to identify non-eclipsing binary systems, producing a sample whose selection effects differ from those of any eclipsing binary catalogue.
We used the BEER algorithm (Faigler et al. 2011, 2013, 2015a, 2015b), which fits for all three of these effects, to search through the light-curves of 9,000,000 targets derived from the TESS full-frame images, and selected 50,000 candidate binaries with orbital periods < 7 days. We will present an overview of this sample, including its selection effects and contaminants, and we will show how the sample can be used to illuminate the underlying population of short-period binaries, in particular the distributions of periods and masses.
In addition, hidden among the sample are likely to be a number of binaries with non-accreting neutron star or black hole companions. We will demonstrate how we have selected promising candidates for such compact binaries, and present our preliminary attempts to follow up on these candidates.
poster number: 8.13 | zenodo
Michael C. Kunz
(Space Telescope Science Institute)
Susan Mullally, STScI
Greg Sloan, STScI, UNC
JJ Hermes, Boston University
Calibration of the science instruments of the James Webb Space Telescope (JWST) is performed using ‘standard candle’ stars. Their spectral types include white dwarfs, A, and G stars because they can be modeled to high accuracy. Selecting stars which give off the same amount of light within 2% allows accurate modeling of stellar objects. Therefore, stars which vary in brightness because of pulsation, rotation, eclipses, flares or any other reason may need to be removed from the list of candidates. The Transiting Exoplanet Survey Satellite (TESS) has observed 35 of the candidate calibration stars. We examined the TESS light curves for evidence of periodic and transient phenomena and report on any detected variability. Using lomb-scargle periodograms, we looked for any significant periodic signals less than 10 days. We detected several variable stars in the set, and the peak to peak amplitudes in one were as large as .3%.
poster number: 8.14 | zenodo
Mike Reed
(Missouri State University)
Roy Ostensen (Missouri State University and Recogito AS, Norway) John Telting (Nordic Optical Telescope and Aarhus University, Denmark)
During its primary mission, TESS observed about 1,000 of our target Subdwarf B (sdB) stars, from which we anticipate about 200 will be pulsating. This will allow an ensemble analysis of these interesting extreme horizontal branch stars, probing their interior structures. This poster will report our preliminary analyses and results of the first few tens of discovered pulsators.
poster number: 8.15 | zenodo
Mirjam Bogner
(Institut fuer Astronomie und Astrophysik Tuebingen)
Beate Stelzer (Institut fuer Astronomie und Astrophysik Tuebingen; INAF - Osservatorio Astronomico di Palermo), Stefanie Raetz (Institut fuer Astronomie und Astrophysik Tuebingen)
I present an analysis of starspot modulation and flares in the TESS light curves of 112 M dwarfs with a TESS magnitude <=11.5 that are listed in the TESS Habitable Zone Star Catalog (HZCat, Kaltenegger et al. 2019). Understanding the magnetic activity of these potential exoplanet host stars is crucial for planet characterizations since an active, flaring host star might impact planetary habitability. Our sample is of particular interest as it comprises stars in the HZCat with sufficiently long TESS observation times for planets to be detected in the entire habitable zone. We detected more than 2000 optical flares in this sample and I discuss the relation of flares with spectral type and rotation period. I also present flare frequency distributions and the flux reaching the habitable zone during flare events.
poster number: 8.16 | zenodo
Murat Uzundag
(Universidad de Valparaiso & ESO)
Murat Uzundag, Alejandro H. Córsico, S. O. Kepler, Leandro G. Althaus
Pulsating white dwarfs (WD) and pre-WDs constitute a well established class of variable stars that exhibit pulsation periods in the range 100-7000 s, associated to low-order nonradial gravity (g) modes. White-dwarf asteroseismology has undergone substantial progress, thanks to the availability of space missions such as Kepler and TESS. In this talk, I will concentrate on pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS. GW Vir stars are pulsating PG1159 stars, that is, pulsating hot hydrogen (H)-deficient, carbon (C)-, oxygen (O)-, helium (He)-rich white dwarf (WD) and pre-WD stars. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize new GW Vir stars.
poster number: 8.17 | zenodo
Natascha Barac
(University of Sydney)
Timothy R. Bedding (University of Sydney); Simon J. Murphy (University of Sydney); Daniel R. Hey (University of Sydney)
The TESS mission delivers high-precision space photometry for almost the full sky, enabling us to measure more precisely and homogenously the dominant modes of pulsating stars. We have used TESS light curves to study catalogued δ Sct stars and measure their dominant oscillation modes. We aim to use our revised data to place these targets more accurately in the period-luminosity diagram.
We look at δ Sct stars from the catalogues of Rodriguez et al. (2000) and Chang et al. (2013), which compile the observational properties of known δ Sct variables from the literature. Both catalogues are compiled from heterogeneous, ground-based measurements, where some targets have been observed for only one or two nights.
We find that lower-amplitude stars have greater error in their published dominant modes, likely due to poor SNR from ground-based observations. Discrepancies in dominant modes may also be due to amplitude modulation. Our P–L diagram shows a strong fundamental-mode ridge, and we find an excess of stars lying on a second ridge, with dominant oscillation periods half that of the predicted fundamental mode. We further demonstrate the value of the P–L diagram in distinguishing δ Sct stars from other pulsators.
poster number: 8.18 | zenodo
Nikki Miller
(Keele University)
Pierre Maxted, Keele University
There is an urgent need for benchmark stars with direct and precise effective temperature measurements. Few standard stars currently available have effective temperature measurements that meet the required accuracy for calibrating temperature indicators for cool dwarf stars (+/- 50K or better). The recent availability of TESS light curves and Gaia parallaxes has made it possible to revisit the fundamental approach of deriving effective temperature for stars in eclipsing binaries (EBs). We present a new method that uses TESS light curves of EBs, Gaia parallaxes and multi-wavelength photometry to obtain very accurate fundamental effective temperatures. These measurements can be used to establish a set of benchmark stars for next-generation surveys. Initial results from the method include the F7V+K0IV binary AI Phoenicis, with T1 = 6199 +/- 22 K and T2 = 5094 +/- 16 K (Miller, Maxted & Smalley, 2020), and the newly identified system ASAS J051753-5406.0 (CPD-54 810), for which we present our preliminary results.
poster number: 8.19 | zenodo
Noel Richardson
(Embry-Riddle Aeronautical University )
Herbert Pablo (AAVSO)
The O8.5III star CC Cas is in a 3.336 d eclipsing binary system that was observed in Sectors 18 and 19 of the TESS mission. We collected nearly 40 new spectra of the binary in the last year, which have been measured to determine both the primary and secondary star velocities. We have begun modeling the system’s light curve and radial velocity curve with the PHysics Of Eclipsing BinariEs (PHOEBE) code. We will present modern masses, radii, and temperatures of this O star binary in this poster presentation based on the TESS data and new radial velocities.
poster number: 8.20 | zenodo
Nolan Grieves
(University of Geneva)
François Bouchy, University of Geneva
The transition between brown dwarfs and low-mass stars is defined by the onset of hydrogen fusion in the core of an object. Current studies typically separate these objects at 80 Jupiter masses. However, this transition mass is dependent on each object’s environment and composition, with models suggesting a transition mass from 73 to 96 Jupiter masses. Here we present five companions discovered by TESS that are in this mass range transiting main sequence stars. We put them in context by exploring the properties of known transiting brown dwarfs and low-mass stars. We also discuss possible distinct characteristics for these separate populations including orbital properties as well as host star effective temperature and metallicity.
poster number: 8.21 | zenodo
Paulo Miles-Páez
(European Southern Observatory)
Paulo A. Miles-Páez (ESO)
We report the detection of photometric variability in the M7.5 binary star VHS J1256-1257AB using archival data from TESS and Spitzer. The optical and infrared light curves periodically exhibit epochs of quasi-sinusoidal modulation followed by others of stochastic variability, which resembles the beat pattern created by two waves of similar frequencies that interfere with each other. Our two-waves model shows that the components of VHS J1256-1257AB rotate with periods of 2.0782 ± 0.0004 h and 2.1342 ± 0.0003 h. As a result the fluxes of the equal-brightness VHS J1256-1257A and B alternate states of phase and anti-phase, explaining the observed photometric variability in their combined light. This is only the first example of several beat-patterns revealed by TESS in different binaries .
poster number: 8.22 | zenodo
Pia Cortes-Zuleta
(Laboratoire d'Astrophysique de Marseille)
Pia Cortes-Zuleta, Laboratoire d'Astrophysique de Marseille
Isabelle Boisse, Laboratoire d'Astrophysique de Marseille
the SPIRou team
the SOPHIE team
M-dwarfs are the most abundant stars in our galaxy and interesting targets for exoplanet surveys. Dedicated radial velocity (RV) surveys of M-dwarfs are being performed by the spectrographs SOPHIE and SPIRou, in the optical and near-infrared regimes, respectively. Both aim to search and characterize small planets around nearby M-dwarfs. Currently, the main limitation to detect these planets around M-dwarfs is the presence of stellar activity. Magnetic chromospheric effects introduce spurious RV signals that hamper the detection of exoplanets. In the optical regime, the H_\alpha index has been the standard for disentangling the stellar activity and the planet signals. However, the nIR domain lacks good independent spectral activity indicators, thus the importance of combining optical and nIR data to constrain chromospheric effects. From the photometric side, TESS provides a unique opportunity to study the rotational modulated variability of M-dwarfs. Combining SOPHIE and SPIRou spectra, and TESS photometry, we aim to characterize the stellar activity of the active M-dwarf Gl205. We will present our results on constraining the rotational period, the sources of variability, and our search for new activity indicators in the nIR.
poster number: 8.23 | zenodo
Pragati Pradhan
(MIT Kavli Institute for Astrophysics and Space Research)
Hans Moritz Guenther + MIT Kavli Institute for Astrophysics and Space Research, David Huenemoerder + MIT Kavli Institute for Astrophysics and Space Research
We present a comparison between the plasma properties of accreting Classical T-Tauri Stars (CTTS) and the coronal Main Sequence (MS) stars seen with Chandra/HETG and the characteristics of their TESS lightcurves. We find that the soft excess (H/He; temperature diagnostics) of lines like Si, Mg, Ne, O versus these line luminosities exhibit the same positive correlation independent of the flaring activity of the stars during their Chandra observations. This is contrary to our expectation that X-ray flares should cause increased plasma temperature and demonstrate a need for detailed flare characterization in optical and X-rays. While numerous flares are observed in X-rays, huge flares - especially for bright stars - are also seen in optical. Our preliminary results also show that prototypical CTTS TW Hydrae exhibit smaller density for lower temperature and is distinguished clearly in the Ne X/Ne IX versus O VIII/O VII plot compared to other MS stars. We will discuss the importance of synergy between Chandra/HETG and TESS to understand the flaring characteristics of these bright young stars, other physical measurements (e.g., rotation periods) with TESS and X-ray behavior with Chandra
poster number: 8.24 | zenodo
Przemysław Mikołajczyk
(Astronomical Institute, University of Wrocław)
Ewa Niemczura, Krzysztof Kotysz, Tomasz Różański. All have the same affiliation
Mercury-manganese (HgMn) stars have spectral types B7-B9 and luminosity classes III-V. They are classified by a strong line of Hg II at 398.39 nm and several lines of Mn II visible in the blue part of the spectrum. Abundance anomalies found in HgMn stars are due to atomic diffusion processes, which are very sensitive to mixing motions. Hence, it is not surprising that HgMn stars are slow rotators (vsini <75 km/s) and often dwell in binary systems. It is assumed that HgMn stars are non-magnetic chemically peculiar stars, however weak magnetic fields have been detected for some of them (e.g. Mathys and Hubrig 1995). In addition, periodic variability was discovered in the spectra of some HgMn stars, what may indicate inhomogeneous distribution of chemical elements on the surface and indirectly the presence of magnetic fields. However, investigations of the photometric variability of HgMn stars are still unexpectedly rare considering available data, both ground-based and satellite. Here we present the results of TESS photometry analysis for more than 100 known HgMn stars. Most stars in our sample appear to be variables, both known and new-found ones. Binarity, rotational modulation and internal pulsations are discussed as mechanisms.
poster number: 9.01 | zenodo
Rafael A. Garcia
(Astrophysics Division CEA/Saclay)
R.A. García^1, S. Mathur^2,3, J. González Otero^3, A.R.G. Santos^4, S. Breton^1
^1 AIM, CEA, CNRS, Université Paris-Saclay, Université de Paris, Sorbonne Paris Cité, F-91191 Gif-sur-Yvette, France
^2 Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain
^3 Universidad de La Laguna (ULL), Departamento de Astrofísica, E-38206 La Laguna, Tenerife, Spain
^4 Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
Evolution of surface magnetic features in the star, such as stellar spots or faculae, can leave a signature in the lightcurves. These features allow us to study the surface rotation period, Prot, of stars. However, the length of the observations is an important limiting factor to determine reliable Prot. Indeed, it is commonly accepted that it is necessary to observe for a period longer than 2-3 times Prot in order to properly determine it. But even when stars are observed for this long (more easily reachable for fast-rotating stars), the observation may happen during a minimum of magnetic activity, which can hamper the Prot detection. It is then challenging to assess the reliability of the extracted Prot as well as the probability of detecting it given the 27-day observation length for the majority of TESS targets. Starting from 55,000 stars with reliable Prot observed by Kepler (Santos et al. 2019, 2021, Breton et al. 2021), 2,500,000 light curves were created to mimic TESS 27-d observations. In this work we present the results we have obtained setting realistic limits on the longest reliable Prot as well as the probability associated to the measurement as a function of different stellar parameters for the entire sample.
poster number: 9.02 | zenodo
Rahul Jayaraman
(Massachusetts Institute of Technology)
Rahul Jayaraman (MIT Kavli Institute + Department of Physics, Cambridge, MA, USA)
Saul Rappaport (MIT Kavli Institute + Department of Physics, Cambridge, MA, USA)
Tamás Borkovits (Baja Astronomical Observatory of University of Szeged, Szeged, Hungary)
Theodor Pribulla (Astronomical Institute of the Slovak Academy of Sciences, Tatranská Lomnica, Slovakia)
Richard Komžik (Astronomical Institute of the Slovak Academy of Sciences, Tatranská Lomnica, Slovakia)
Tibor Mitnyan (Baja Astronomical Observatory of University of Szeged, Szeged, Hungary)
Petr Zasche (Astronomical Institute, Charles University, Praha, Czech Republic)
Andrei Tokovinin (Cerro Tololo Inter-American Observatory | NSF's NOIRLab, La Serena, Chile)
Joseph E. Rodriguez Jr. (Michigan State University, Lansing, MI, USA)
Ivan Terentev (Citizen Scientist, c/o Zooniverse, Department of Physics, University of Oxford, UK)
Mark Omohundro (Citizen Scientist, c/o Zooniverse, Department of Physics, University of Oxford, UK)
Robert Gagliano (Amateur Astronomer, Glendale, AZ, USA)
Tom Jacobs (Amateur Astronomer, Bellevue, WA, USA)
Martti Kristiansen (National Space Institute, Technical University of Denmark, Lyngby, Denmark)
Daryll LaCourse (Amateur Astronomer, Marysville, WA, USA)
Hans Schwengeler (Citizen Scientist, c/o Zooniverse, Department of Physics, University of Oxford, UK)
Andrew Vanderburg (Department of Astronomy, University of Wisconsin-Madison, Madison, WI, USA)
Using TESS observations, we have found that BU Canis Minoris (BU CMi, TIC 271204362), a known bright eclipsing binary, is actually a quadruply-eclipsing quadruple star system (2+2), with its two component binaries having periods of 2.9 and 3.2 days. The outer orbit has a period of ~120 days, the shortest known among all quadruple star systems. We used eclipse times and durations from TESS sectors 7 and 34, as well as KELT and MASCARA data, to identify and characterize strongly driven apsidal precession in BU CMi. Both binaries’ apsides are found to precess with a period of ~25 years.
We obtained 39 high-resolution spectra of BU CMi, which suggest that its four components are early-type B/A stars with T_eff~11,000 K. However, disentangling the four individual radial velocities from the spectral lines has proven difficult in this system; so, we iteratively and simultaneously analyzed the spectra and orbital motion. This helped establish the outer period and estimate its semimajor axis. We also used a photodynamics code to analyze eclipse shapes and timing to independently evaluate all three orbits. Future work on BU CMi will involve further ground-based photometry to refine its system parameters, after the sun moves away from it.
poster number: 9.03 | zenodo
Rishi R Paudel
(NASA Goddard/UMBC)
Thomas Barclay (NASA Goddard Space Flight Center; University of Maryland Baltimore County), Joshua Schlieder (NASA Goddard Space Flight Center), Elisa Quintana (NASA Goddard Space Flight Center), Emily Gilbert (University of Chicago; NASA Goddard Space Flight Center), Laura Vega (Vanderbilt University; NASA Goddard Space Flight Center), Allison Youngblood (Laboratory for Atmospheric and Space Physics), Michele Silverstein (NASA Goddard Space Flight Center), Teresa Monsue (NASA Goddard Space Flight Center), Daniel Huber (University of Hawaii)
We present the first results from our large program studying nearby active flaring M dwarfs using multi-wavelength datasets. We focus on the flaring M dwarf EV Lac, which has been known as a flare star for at least 65 years. We acquired data of EV Lac using 5 different observatories: NASA's TESS mission, NASA's Neil Gehrels Swift Observatory ($Swift$), NASA's Neutron Interior Composition Explorer (NICER) and two ground based telescopes (University of Hawaii 2.2-m (UH88) and Las Cumbres Observatory Global Telescope (LCOGT) Network), to span a comprehensive, simultaneous wavelength coverage of flaring events. We identified 56 flares in the TESS light curve, 9 flares in the $Swift$ $UVM2$ light curve, 14 flares in the NICER X-ray light curve, and 1 flare in the LCOGT light curve. However, we did not identify flares in the $Swift$ XRT light curve or UH88 spectrum. We find that the FFDs of TESS and NICER flares have comparable slopes, $\beta_{T}$ = -0.67$\pm$0.09 and $\beta_{N}$ = -0.64$\pm$0.19, and that the FFD of UVOT flares has a shallower slope ($\beta_{U}$ = -0.38$\pm$0.13). Our results will be useful to model and estimate the impacts of strong flares on the atmospheres of planets orbiting M dwarfs.
poster number: 9.04 | zenodo
Ryohei Hosokawa
(Tokyo Institute of Technology)
MAXI Team(Riken), N.Kawai(Tokyo Tech), M.Uemura(Hiroshima university.), H. Maehara (NAOJ),
Abstract We searched for the correlation between X-ray and optical variabilities of X-ray binaries by comparing the light curves observed by MAXI and TESS at the same time. First, from MAXI public light curves of more than 400 X-ray sources, We chose 33 sources which show appreciable modulations in X-ray and are observed in TESS (at Nov 2019). Then I obtained light curves of these 33 sources from TESS Full-frame images using 'eleanor'. Among them, Cen X-3 and SMC X-1 have been observed by both satellites at the same time for 54 days and showed clear modulations in both X-ray and optical light. We performed the modeling of optical light curves for these X-ray binaries based on a simple geometric model. In our model, tidal and rotational distortion, limb-darkening and gravity darkening effects are taken into account. In addition, the effect of the presence of a disk is also included. I'll discuss light curves of SMC X-1 and Cen X-3 using this model and give constraints on their parameters
poster number: 9.05 | zenodo
Sebastián López Skrzypinski
(Universidad Complutense de Madrid (UCM))
Skrzypinski, S. L. (UCM); Revilla, D. (UCM); Montes, D. (UCM);
Caballero, J. A. (CAB); Béjar, V. J. S. (IAC); Shan, Y. (IAG);
Morales-Calderón, M. (CAB); Vanaverbeke, S. (AstroLAB); et al.
CARMENES is a spectrograph built for the 3.5 m telescope at the Calar Alto Observatory. The main aim is to detect low mass planets around M dwarfs. In order to achieve this goal, it is critical to characterize the monitored stars, especially their activity and rotation. Using TESS data from its first two cycles, we studied the rotation and activity in the 2-min cadence time series of 1249 M dwarfs in the CARMENES input catalog. Next, with the Generalised Lomb-Scargle periodogram, we measured 222 rotation periods between 0.2 d and 10 d. Of them, 137 are consistent with their literature counterparts and 75 were previously unknown. Using splines and Fourier polynomials, we detrended the light curves of the stars for which we found a rotational period in order to look for flaring activity. We measured energies between 10^{31} erg and 10^{35} erg of 1922 flares of 225 periodic M dwarfs. We fitted the rate of flares with energies greater than 10^{33.7} erg to a power law of the form NdE \propto E^{-\alpha} dE and determined \alpha to be 2.17+/-0.02.
poster number: 9.06 | zenodo
Siemen Burssens
(Instituut voor Sterrenkunde, KU Leuven)
Dominic Bowman - Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
Sergio Simón-Díaz - Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain & Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
Conny Aerts - Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium &
Department of Astrophysics, IMAPP, Radboud University Nijmegen, 6500 GL Nijmegen, The Netherlands &
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
The evolution of high mass stars (>8M_sun) is strongly dictated by their interior structure, specifically the mixing processes near the core and in the surrounding envelope. Asteroseismology can open up these stellar interiors but unfortunately Kepler did not provide any high-mass stars with identified modes for this endeavour. The TESS space mission is remedying this by observing a large number of high-mass stars allowing us to construct an asteroseismic sample of OB pulsators and open up the way to their asteroseismic sounding. In this talk we present a detailed analysis of the high-mass pulsator HD192575 (B0.5 V) using its 1-year TESS light curve. HD192575 is among the first of its variability class to be observed uninterruptedly during such a long time and the resulting high frequency precision of the measured pulsations allows for in-depth modelling. In our novel modelling strategy we use a maximum likelihood estimator which incorporates correlations among the parameters and theoretical uncertainties due to unknown input physics of stellar models. This allows us to derive a precise mass, internal mixing, and age from zonal modes, as well as its interior rotation from detected rotationally split multiplets of low-degree modes.
poster number: 9.07 | zenodo
Spencer C. Wallace
(University of Washington)
James R. Davenport (University of Washington)
Tyler A. Gordon (University of Washington)
We present the results of an automated search for superflare events using 2 minute light curve data from the first two years of the TESS mission (sectors 1-26). In order to determine the properties of the targets and to measure flare energies, we restrict ourselves to objects which have distance and color measurements from Gaia. Flare events are found by first detrending the light curves using an iterative gaussian process fit and then searching for outliers with a change-point analysis technique. In total, we identify 27,229 flare events from 7,260 different stars. As a byproduct of the gaussian process detrending, we also provide robust rotation period measurements for about 80,000 stars in the sample. We find a decreasing correlation between flare rate and rotation period, and also find a decreasing trend between flare rate and galactic height. Both of these results are consistent with flare rate diminishing with age.
poster number: 9.08 | zenodo
Stefanie Raetz
(Institute for Astronomy and Astrophysics Tuebingen (IAAT))
B. Stelzer (IAAT, INAF-Palermo), E. Magaudda (IAAT)
Studies of the rotation and activity of M type stars are essential to enhance our understanding of stellar dynamos and angular momentum evolution. Using the outstanding photometric capabilities of space telescopes rotation signals even with low amplitudes can be investigated in up to now unrivaled detail. By combining data of Kepler/K2 and TESS the star spot activity of M dwarfs can be monitored on a decade timescale. In the framework of our study on the rotation-activity relation for M dwarfs that is based on the Lepine and Gaidos (2011) catalog we also aim at an investigation of the long-term activity. While K2 was observing fields distributed around the ecliptic plane, the TESS prime mission was oriented along a line of ecliptic longitude with one camera centered on an ecliptic pole. Due to these different observing strategies, the overlap between K2 and TESS is marginal. However, 45 stars from our sample were observed with both missions of which four targets were analyzed in more detail. In my contribution I will present our results of the combined K2 and TESS stellar activity studies. Furthermore, we will show that combining missions like K2 and TESS are a promising method for detecting stellar activity cycles.
poster number: 9.09 | zenodo
Stephanie T. Douglas
(Lafayette College)
Jose Perez Chavez (Texas State), Phillip Cargile (CfA), Chelsea Huang (MIT, USQ), Nicholas Wright (Keele), George Zhou (USQ), Steve Howell (NASA ARC), Adam Kraus (UT Austin)
As Solar-type stars approach the main sequence, they contract and spin more rapidly; once they reach the main sequence, they stop contracting and their spin speed decreases. This spin-down is thought to be caused by angular momentum lost via stellar winds, but there are currently limited constraints on model behavior at this critical age. We use TESS full-frame images to measure rotation periods (Prot) for stars in five young open clusters in the Southern Sky. We have also surveyed 35 FGK rotators in these ZAMS clusters using speckle imaging at Gemini-South. We detect 5 candidate companions in these young clusters. We will present preliminary results on the rotation of Solar-type stars at the ZAMS, and the impact of multiplicity on the ZAMS Prot distribution.
poster number: 9.11 | zenodo
Tamás Borkovits
(Baja Astronomical Observatory of Szeged University)
S. A. Rappaport (Kavli Institute, M.I.T.) , T. Mitnyan (SzTE Baja Observatory, Hungary), A. Pál (Konkoly Observatory, Budapest, Hungary), P. F. L. Maxted (Keele University, Staffordshire, U.K.), I. B. Bíró (SzTE Baja Observatory, Hungary), I. Csányi (SzTE Baja Observatory, Hungary), Z. Garai (MTA-ELTE Exoplanet Research Group, Szombathely, Hungary), B. L. Gary (Amateur Astronomer, Hereford Arizona Observatory, AZ), F.-J. Hambsch (Amateur Astronomer, Vereniging Voor Sterrenkunde, Belgium), T. G. Kaye (Amateur Astronomer, Patterson Observatory, AZ), T. Pribulla (ELTE Gothard Observatory, Szombathely, Hungary), T. G. Tan (Amateur Astronomer, Perth, AUS)
With TESS we have discovered about a dozen new triply eclipsing triple stars, i.e., hierarchical triple or multiple stellar systems where the outer stellar component recurrently eclipses the inner eclipsing binary or is eclipsed by it. The outer orbital periods of these systems were found to be between 1.5 months and ~1 year, and therefore, in most cases, the orbits of the EBs depart significantly from simple Keplerian motion which is manifested by strong eclipse timing variations (ETVs). For a few case studies we present the full process of studying such systems beginning with their identification through an initial characterization of the 'third body' eclipses, to follow-up ground-based observations and the use of archival data, and then to the final complex photodynamical modelling. The latter includes joint (multi-epoch, multi-band) lightcurve, ETV curve, radial velocity curve (if available), and composite SED analyses. Such studies can allow for the complete characterization of the system parameters, including the detailed orbital architecture. A surprising number of overall flat systems have been found.
poster number: 9.12 | zenodo
Tara Fetherolf
(University of California, Riverside)
Josh Pepper (Lehigh University), Emilie Simpson (University of California, Riverside), Stephen Kane (University of California, Riverside), Teo Mocnik (Gemini Observatory)
The shape and periodic nature of stellar light curves can uncover important information about a star’s intrinsic properties, in addition to revealing possible companions. TESS has obtained high-precision space-based time-series photometry of nearly the entire sky, allowing for a large-scale study of stellar variability that is not sensitive to the diurnal limitation of ground-based surveys. We search for periodicity in ~230,000 stars that were observed at 2-minute cadence during the TESS primary mission and identify ~55,000 stars with significant sinusoidal variability on timescales of 0.01-13 days that could be attributed to rotational modulations, stellar pulsations, or binarity. We will discuss the population statistics for stars in our sinusoidal stellar variability catalog and make comparisons with those at similar timescales (<13 days) detected by Kepler. Our stellar variability catalog will be a valuable resource to the stellar astrophysics and exoplanet communities, in that it will aid 1) studying the characteristics of periodic variable stars; 2) understanding interactions between host star variability and planetary atmospheres; and 3) identifying false positives caused by stellar variability for future planet candidates.
poster number: 9.13 | zenodo
Teresa Monsue
(NASA GSFC - USRA)
Joshua Schlieder (NASA GSFC), Laura Vega (NASA GSFC, UMD), Rishi R. Paudel (NASA GSFC, UMBC), Tom Barclay (NASA GSFC, UMBC), Emily A. Gilbert (UChicago), Michele Silverstein (NASA GSFC, USRA), and Elisa V. Quintana (NASA GSFC)
Stellar atmospheres encompass an abundance of waves and oscillations. This includes those associated with flares. Oscillatory and pulsating signatures, commonly known as quasi-periodic pulsations (QPPs), are observed at many wavelengths during both solar and stellar flares. These oscillatory phenomena travel on magnetic field lines in the star's atmosphere and can provide insight into the astrophysical processes of flares. We present a study of flare oscillations in nearby, active M dwarf stars. We use high cadence photometry from TESS (20 sec, optical) and Swift (~1 sec, UV) to measure QPP properties and place constraints on the fundamental processes driving flares at different layers of the stellar atmosphere.
poster number: 9.14 | zenodo
Thomas Steindl
(University of Innsbruck)
Knostanze Zwintz (University of Innsbruck), T. G. Barnes (University of Texas at Austin), Marco Müllner (University of Innsbruck), Eduard I. Vorobyov (University of Vienna)
Stellar mass is clearly the most important parameter in stellar evolution, governing the entire evolution from the pre-main sequence to the final fate of the star. Despite that, our theoretical stellar models often ignore how stars have obtained their main sequence mass, although it is commonly accepted that the collapse of molecular clouds creates stellar seeds that subsequently accrete material from their surroundings. In this poster, we present calculations of the pre-main sequence evolution starting from the accreting phase. We compare these evolutionary tracks to spectroscopic parameters of young stellar objects and constrain free parameters in the accretion modelling. We investigate the pulsational instability of the calculated pre-main sequence models by calculating instability regions and comparing their positions to a sample of pre-main sequence pulsators. The latter are compiled from the literature and extended by discoveries made from TESS data. Finally, we present the first candidate M-type pulsating star discovered in TESS full-frame images.
poster number: 9.15 | zenodo
Tiago Campante
(Instituto de Astrofísica e Ciências do Espaço)
Kepler asteroseismology has played an important role in the characterization of host stars and their planetary systems. Selection biases, however, meant that this synergy would mostly remain restricted to main-sequence stars. The advent of TESS has since lifted this restriction. In this talk, I will be presenting the asteroseismic analysis of two red-giant hosts. KOI-3886, observed by Kepler over 4 years and later by TESS, has been a longtime candidate host. iota Dra, known to host a planet in a highly eccentric orbit, was observed by TESS over 5 Sectors. We measured individual mode frequencies over 7 radial orders for both stars. We next conducted state-of-the-art stellar modeling, having both considered all observed modes and p-dominated mixed modes only. The precise (~6%) seismic mass derived for iota Dra was combined with new RV observations to detect an additional long-period companion. Regarding KOI-3886, asteroseismology was key in revealing the planet candidate as a false positive and reinterpreting the system as an eclipsing brown dwarf in a hierarchical triple. This brings to light the importance of asteroseismology in the study of orbital dynamics off the main sequence and its lesser known role in candidate vetting.
poster number: 9.16 | zenodo
Tibor Mitnyan
(Baja Astronomical Observatory of University of Szeged)
T. Mitnyan (Baja Astronomical Observatory of University of Szeged, Hungary), T. Borkovits (Baja Astronomical Observatory of University of Szeged, Hungary), A. Pál (Konkoly Observatory, Hungary), T. Hajdu (Konkoly Observatory, Hungary)
There are thousands of previously known and newly identified eclipsing binaries observed almost continuously for nearly a year long during Year 2 of the TESS mission. These precise and unique data sets give us an opportunity to measure a significant amount of their eclipse times on a time-scale comparable to the usual outer orbital periods of compact hierarchical triple stellar systems (below 1-2 years). In our project, we obtain the light curves from TESS Full-Frame Images of more than 4,000 eclipsing binaries observed at least during 8 Sectors and determine their eclipse timing variations in order to search for the signals of third-body perturbations and/or light travel time effect caused by an unseen, more distant component. We present orbital solutions for the identified triple systems and statistical considerations will also be discussed.
poster number: 9.17 | zenodo
Tilaksingh Pawar
(Nicolaus Copernicus Astronomical Center)
T. Pawar (1), K. Hełminiak (1), R.S. Rathour (2), A. Moharana (1), F. Marcadon (1), M. Konacki (2). Affiliations: (1) - Nicolaus Copernicus Astronomical Center, Rabiańska 8, Toruń, Poland. (2) - Nicolaus Copernicus Astronomical Center, Bartycka 18, Warsaw, Poland
TESS has provided us with an unprecedented quality of light curves (LCs), enabling us to study variability at the millimag level. We utilize the high quality 2-min cadence data for the target AI Hydrae to study this eclipsing binary and its delta scuti pulsator component. We model the light curve using JKTEBOP, simultaneously fitting sinusoidal and polynomial functions to account for the LC variability caused by the pulsations. This modelling is complimented further by frequency analysis of the residual pulsation signals and analysis of spectra observed at different orbital phases using HIDES spectrograph. This helps us obtain accurate values of orbital and stellar parameters with robust errors. Additionally, plans of investigating the pulsations from an asteroseismic angle will help us shed some more light on the properties of this delta scuti pulsator.
poster number: 9.18 | zenodo
Tomomi Otani
(Embry-Riddle Aeronautical University)
Andrzej Baran (Embry-Riddle Aeronautical University)
Ted von Hippel (Pedagogical University of Cracow, Missouri State University, Embry-Riddle Aeronautical University)
Brian Herbster (Embry-Riddle Aeronautical University)
Lorena Sanabria (Embry-Riddle Aeronautical University)
Johnathan Hodge (Embry-Riddle Aeronautical University)
Subdwarf B (sdB) stars are extreme horizontal branch stars with high temperature and gravity. The most promising formation scenarios involve close binary star evolution with three different channels: (1) a Common Envelope channel, which can produce short period (P=0.1–10 d) sdB + white dwarf (WD) or main sequence (MS) binaries, (2) a Roche lobe overflow channel, which results in a long period (450 < P < 1400 d) sdB + MS binaries, and (3) a WD merger channel, which can produce single sdB stars. To test these scenarios, population studies in each channel are essential. Approximately 30% of sdB stars show stable pulsations and for these, the pulsation timing method is the effective tool to search for long-period binary systems or single stars. Positive detection of a binary system can be obtained from a periodic change of a pulsation mode phase, which is a consequence of a star’s reflex motion. Consequently, we can confirm single stars by non-detection of such a phase variation. We employ TESS and follow-up ground-based observations to search for companions to sdB stars via this pulsating timing method. We further supplement these constraints by comparing our targets in color-color diagrams to different types of sdB binaries.
poster number: 9.19 | zenodo
Yuta Notsu
(CU Boulder/LASP/NSO/Tokyo Tech)
Adam Kowalski (1,2), Hiroyuki Maehara (3), Kosuke Namekata (3,4),
Satoshi Honda (5), Teruaki Enoto (6), Kenji Hamaguchi (7,8), Isaiah Tristan (1,2),
Suzanne Hawley (9), James Davenport (9), Soshi Okamoto (4), Kai Ikuta (4),
Daisaku Nogami (4), Kazunari Shibata (4)
(1) University of Colorado Boulder (2) National Solar Observatory, (3) NAOJ, (4) Kyoto University, (5) University of Hyogo, (6) RIKEN, (7) NASA/GSFC, (8) UMBC, (9) University of Washington
Flares are releases of magnetic energy in the stellar atmosphere, and they have strong emissions from radio to X-rays. During some M dwarf flares, chromospheric line profiles show blue asymmetries, although red asymmetries are more commonly observed in solar flares. Similar enhancements of the blue wings of Balmer lines may provide clues for investigating the early phases of stellar coronal mass ejections (CMEs), but this is still controversial. Thus, we need more observations to understand the relationship between mass ejections and flares. We have conducted simultaneous spectroscopic and photometric observations of mid M dwarf flare stars using APO 3.5m/ARCES, SMARTS1.5m/CHIRON, TESS, and etc. During 34 night observations, we detected 48 flares in Balmer lines (e.g. Hα). At least 7 flares show clear blue asymmetries. Blue asymmetry durations are different among the 7 events (20min ~ 2hr). These results suggest upward flows of chromospheric plasma during flare events. By assuming that the blue asymmetries were caused by prominence eruptions, we estimated the mass and kinetic energy. The estimated masses are comparable to expectations from the empirical relation between the flare X-ray energy and mass of solar CMEs.
poster number: 9.20 | zenodo
Zach Claytor
(University of Hawaii)
Jennifer van Saders, University of Hawaii
Joe Llama, Lowell Observatory
Peter Sadowski, University of Hawaii
Brandon Quach, Caltech
Ellis Avallone, University of Hawaii
TESS is poised to increase the number of stellar rotation period estimates by an order of magnitude, but the mission’s systematics have complicated period searches. While several efforts attempt to solve this problem by removing systematics, standard methods of data reduction have shown limited success. I will present a method to predict rotation periods from TESS full-frame image light curves using deep learning. This method relies on a training set of simulated light curves convolved with TESS galaxy light curves to emulate the instrumental noise and systematics observed in stellar signals. The simulations include surface differential rotation, spot evolution, and activity level to make the light curves as realistic as possible. Our approach allows the network to learn the difference between rotation signals and TESS systematics. With the added ability to predict uncertainty in the period, we can determine what regions of parameter space the predictions are most credible, producing a reliable set of rotation periods. I will present the first set of rotation periods obtained with this method and explore TESS’s insights to stellar structure and evolution through the lens of rotation.
poster number: 9.21 | zenodo
Lizhou Sha
(University of Wisconsin-Madison)
Andrew Vanderburg, University of Wisconsin-Madison
Chelsea Huang, MIT
David Armstrong, University of Warwick
Rafael Brahm, Universidad Adolfo Ibáñez and Millennium Institute for Astrophysics
Jiayin Dong, Pennsylvannia State University
George Zhou, University of Southern Queensland
We report the discovery of the TOI-2000 system, with a < 3 R_E planet in a 3.10 day orbit interior to a Saturn-mass planet in a 9.13 day orbit, and confirm the latter with RV measurements from CHIRON, FEROS, and HARPS. The TOI-2000 system hosts the smallest and fourth overall hot gas giant known to have a smaller inner companion to date. Because such inner companions are not expected to remain in the system after high-eccentricity migration of the giant planet, TOI-2000 provides further evidence that some hot gas giants may have formed through other mechanisms. We discovered the smaller TOI-2000 b during a systematic BLS search of all MIT Quick Look Pipeline (QLP) light curves for ~ 800 confirmed and candidate hot Jupiter host stars brighter than the 11th TESS magnitude in the TESS prime mission. Combining TESS, Kepler, and K2 hot Jupiters, we calculate a posterior distribution for the occurrence rate of inner companions to transiting hot Jupiters. To date, TOI-2000 joins TOI-1130 as the only systems that host a hot gas giant and a smaller inner planet discovered by TESS during its two-year prime mission, along with WASP-47 and Kepler 730 systems discovered by Kepler.