A Hot Saturn Orbiting An Oscillating Late Subgiant Discovered by TESS
Creators: name: Huber, Daniel
name: Chaplin, William J.
name: Chontos, Ashley
name: Kjeldsen, Hans
name: Christensen-Dalsgaard, Joergen
name: Bedding, Timothy R.
name: Ball, Warrick
name: Brahm, Rafael
name: Espinoza, Nestor
name: Henning, Thomas
name: Jordan, Andres
name: Sarkis, Paula
name: Knudstrup, Emil
name: Albrecht, Simon
name: Grundahl, Frank
name: Andersen, Mads Fredslund
name: Palle, Pere L.
name: Crossfield, Ian
name: Fulton, Benjamin
name: Howard, Andrew W.
name: Isaacson, Howard T.
name: Weiss, Lauren M.
name: Handberg, Rasmus
name: Lund, Mikkel N.
name: Serenelli, Aldo M.
name: Mosumgaard, Jakob
name: Stokholm, Amalie
name: Bierlya, Allyson
name: Buchhave, Lars A.
name: Latham, David W.
name: Quinn, Samuel N.
name: Gaidos, Eric
name: Hirano, Teruyuki
name: Ricker, George R.
name: Vanderspek, Roland K.
name: Seager, Sara
name: Jenkins, Jon M.
name: Winn, Joshua N.
name: Antia, H. M.
name: Appourchaux, Thierry
name: Basu, Sarbani
name: Bell, Keaton J.
name: Benomar, Othman
name: Bonanno, Alfio
name: Buzasi, Derek L.
name: Campante, Tiago L.
name: Orhan, Z. Celik
name: Corsaro, Enrico
name: Cunha, Margarida S.
name: Davies, Guy R.
name: Deheuvels, Sebastien
name: Grunblatt, Samuel K.
name: Hasanzadeh, Amir
name: Di Mauro, Maria Pia
name: Garcia, Rafael A.
name: Gaulme, Patrick
name: Girardi, Leo
name: Guzik, Joyce A.
name: Hon, Marc
name: Jiang, Chen
name: Kallinger, Thomas
name: Kawaler, Steven D.
name: Kuszlewicz, James S.
name: Lebreton, Yveline
name: Li, Tanda
name: Lucas, Miles
name: Lundkvist, Mia S.
name: Mathis, Stephane
name: Mathur, Savita
name: Mazumdar, Anwesh
name: Metcalfe, Travis S.
name: Miglio, Andrea
name: Monteiro, Mario J.
name: Mosser, Benoit
name: Noll, Anthony
name: Nsamba, Benard
name: Mann, Andrew W.
name: Ong, Jia Mian Joel
name: Ortel, S.
name: Pereira, Filipe
name: Ranadive, Pritesh
name: Regulo, Clara
name: Rodrigues, Thaise S.
name: Roxburgh, Ian W.
name: Aguirre, Victor Silva
name: Smalley, Barry
name: Schofield, Mathew
name: Sousa, Sergio G.
name: Stassun, Keivan G.
name: Stello, Dennis
name: Tayar, Jamie
name: White, Timothy R.
name: Verma, Kuldeep
name: Vrard, Mathieu
name: Yildiz, M.
name: Baker, David
name: Bazot, Michael
name: Beichmann, Charles
name: Bergmann, Christoph
name: Bugnet, Lisa
name: Cale, Bryson
name: Carlino, Roberto
name: Cartwright, Scott M.
name: Christiansen, Jessie L.
name: Ciardi, David R.
name: Creevey, Orlagh
name: Dittmann, Jason A.
name: Nascimento, Jose Dias Do
name: van Eylen, Vincent
name: Furesz, Gabor
name: Gagne, Jonathan
name: Gao, Peter
name: Gazeas, Kosmas
name: Giddens, Frank
name: Hall, Oliver
name: Hekker, Saskia
name: Ireland, Michael J.
name: Latouf, Natasha
name: LeBrun, Danny
name: Levine, Alan M
name: Matzko, William
name: Natinsky, Eva
name: Page, Emma
name: Plavchan, Peter
name: Mansouri-Samani, Masoud
name: McCauliff, Sean
name: Mullally, Susan E
name: Orenstein, Brendan
name: Soto, Aylin
name: Paegert, Martin
name: van Saders, Jennifer L.
name: Schnaible, Chloe
name: Soderblom, David R.
name: Szabo, Robert
name: Tanner, Angelle
name: Tinney, C. G.
name: Teske, Johanna
name: Thomas, Alexandra
name: Trampedach, Regner
name: Wright, Duncan
name: Yuan, Thomas T.
name: Zohrabi, Farzaneh
Publisher: name: arXiv
Year: 2019
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the discovery of TOI-197.01, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. TOI-197 (HIP116158) is a bright (V=8.2 mag), spectroscopically classified subgiant which oscillates with an average frequency of about 430 muHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2-minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (2.943+/-0.064 Rsun), mass (1.212 +/- 0.074 Msun) and age (4.9+/-1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a "hot Saturn" (9.17+/-0.33 Rearth) with an orbital period of ~14.3 days, irradiance of 343+/-24 Fearth, moderate mass (60.5 +/- 5.7 Mearth) and density (0.431+/-0.062 gcc). The properties of TOI-197.01 show that the host-star metallicity - planet mass correlation found in sub-Saturns (4-8 Rearth) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ~15%, TOI-197.01 is one of the best characterized Saturn-sized planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.
description: 12 pages (excluding author list and references), 9 figures, 4 tables, accepted for publication in AJ. An electronic version of Table 3 is available as an ancillary file (sidebar on the right)