Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Melissa J. Hobson
Andrés Jordán
E. M. Bryant
R. Brahm
D. Bayliss
J. D. Hartman
G. Á. Bakos
Th. Henning
Jose Manuel Almenara
Khalid Barkaoui
Zouhair Benkhaldoun
Xavier Bonfils
François Bouchy
David Charbonneau
Marion Cointepas
Karen A. Collins
Jason D. Eastman
Mourad Ghachoui
Michaël Gillon
Robert F. Goeke
Abstract： We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry, and confirmed with radial velocities from ESPRESSO, and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of $\mathrm{0.665\pm0.025\,M_J}$ and a radius of $\mathrm{1.017\pm0.044\,R_J}$. It orbits close to its host star, with an orbital period of $\mathrm{2.5926\,d}$, but has an equilibrium temperature of $\mathrm{\approx 604 \, K}$, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of $\mathrm{0.3939\pm0.0030\,M_\odot}$, a radius of $\mathrm{0.3697\pm0.0018\,R_\odot}$, an effective temperature of $\mathrm{3389 \, K}$, and a J-band magnitude of $\mathrm{11.706\pm0.025}$. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M-dwarfs for atmospheric characterization.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Evan Tey
Dan Moldovan
Michelle Kunimoto
Chelsea X. Huang
Avi Shporer
Tansu Daylan
Daniel Muthukrishna
Andrew Vanderburg
Anne Dattilo
George R. Ricker
S. Seager
Abstract： The TESS mission produces 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 have proved effective at differentiating promising astrophysical eclipsing candidates from other phenomena such as stellar variability and systematic instrumental effects in an efficient, unbiased and sustainable manner. This paper presents a high quality dataset containing light curves from the Primary Mission and 1st Extended Mission full frame images and periodic signals detected via Box Least Squares (Kov\'acs et al. 2002; Hartman 2012). The dataset was curated using a thorough manual review process then used to train a neural network called Astronet-Triage-v2. On our test set, for transiting/eclipsing events we achieve a 99.6% recall (true positives over all data with positive labels) at a precision of 75.7% (true positives over all predicted positives). Since 90% of our training data is from the Primary Mission, we also test our ability to generalize on held-out 1st Extended Mission data. Here, we find an area under the precision-recall curve of 0.965, a 4% improvement over Astronet-Triage (Yu et al. 2019). On the TESS Object of Interest (TOI) Catalog through April 2022, a shortlist of planets and planet candidates, Astronet-Triage-v2 is able to recover 3577 out of 4140 TOIs, while Astronet-Triage only recovers 3349 targets at an equal level of precision. In other words, upgrading to Astronet-Triage-v2 helps save at least 200 planet candidates from being lost. The new model is currently used for planet candidate triage in the Quick-Look Pipeline (Huang et al. 2020a,b; Kunimoto et al. 2021).
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Nolan Grieves
François Bouchy
Solène Ulmer-Moll
Samuel Gill
David R. Anderson
Angelica Psaridi
Monika Lendl
Keivan G. Stassun
Jon M. Jenkins
Matthew R. Burleigh
Jack S. Acton
Patricia T. Boyd
Sarah L. Casewell
Philipp Eigmüller
Michael R. Goad
Robert F. Goeke
Maximilian N. Günther
Faith Hawthorn
Beth A. Henderson
Christopher E. Henze
Abstract： We report the discovery of a 1.32$^{+0.10}_{-0.10}$ $\mathrm{M_{\rm Jup}}$
planet orbiting on a 75.12 day period around the G3V $10.8^{+2.1}_{-3.6}$ Gyr
old star TOI-5542 (TIC 466206508; TYC 9086-1210-1). The planet was first
detected by the Transiting Exoplanet Survey Satellite (TESS) as a single
transit event in TESS Sector 13. A second transit was observed 376 days later
in TESS Sector 27. The planetary nature of the object has been confirmed by
ground-based spectroscopic and radial velocity observations from the CORALIE
and HARPS spectrographs. A third transit event was detected by the ground-based
facilities NGTS, EulerCam, and SAAO. We find the planet has a radius of
1.009$^{+0.036}_{-0.035}$ $\mathrm{R_{\rm Jup}}$ and an insolation of
9.6$^{+0.9}_{-0.8}$ $S_{\oplus}$, along with a circular orbit that most likely
formed via disk migration or in situ formation, rather than high-eccentricity
migration mechanisms. Our analysis of the HARPS spectra yields a host star
metallicity of [Fe/H] = $-$0.21$\pm$0.08, which does not follow the traditional
trend of high host star metallicity for giant planets and does not bolster
studies suggesting a difference among low- and high-mass giant planet host star
metallicities. Additionally, when analyzing a sample of 216 well-characterized
giant planets, we find that both high masses (4 $\mathrm{M_{\rm Jup}}$
$
Peer Review Status:Awaiting Review
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