A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS
Makaleler > Tam Makale · 2019
Yazarlar: Daniel Huber, William J. Chaplin, Ashley Chontos, Hans Kjeldsen, Jørgen Christensen-Dalsgaard, Timothy R. Bedding, Warrick Ball, Rafael Brahm, Nestor Espinoza, Thomas Henning, Andrés Jordán, Paula Sarkis, Emil Knudstrup, Simon Albrecht, Frank Grundahl, Mads Fredslund Andersen, Pere L. Pallé, Ian Crossfield, Benjamin Fulton, Andrew W. Howard, Howard T. Isaacson, Lauren M. Weiss, Rasmus Handberg, Mikkel N. Lund, Aldo M. Serenelli, Jakob Rørsted Mosumgaard, Amalie Stokholm, Allyson Bieryla, Lars A. Buchhave, David W. Latham, Samuel N. Quinn, Eric Gaidos, Teruyuki Hirano, George R. Ricker, Roland K. Vanderspek, Sara Seager, Jon M. Jenkins, Joshua N. Winn, H. M. Antia, Thierry Appourchaux, Sarbani Basu, Keaton J. Bell, Othman Benomar, Alfio Bonanno, Derek L. Buzasi, Tiago L. Campante, Z. Çelik Orhan, Enrico Corsaro, Margarida S. Cunha, Guy R. Davies, Sebastien Deheuvels, Samuel K. Grunblatt, Amir Hasanzadeh, Maria Pia Di Mauro, Rafael A. García, Patrick Gaulme, Léo Girardi, Joyce A. Guzik, Marc Hon, Chen Jiang, Thomas Kallinger, Steven D. Kawaler, James S. Kuszlewicz, Yveline Lebreton, Tanda Li, Miles Lucas, Mia S. Lundkvist, Andrew W. Mann, Stéphane Mathis, Savita Mathur, Anwesh Mazumdar, Travis S. Metcalfe, Andrea Miglio, Mário J. P. F. G. Monteiro, Benoit Mosser, Anthony Noll, Benard Nsamba, Jia Mian Joel Ong, S. Örtel, Filipe Pereira, Pritesh Ranadive, Clara Régulo, Thaíse S. Rodrigues, Ian W. Roxburgh, Victor Silva Aguirre, Barry Smalley, Mathew Schofield, Sérgio G. Sousa, Keivan G. Stassun, Dennis Stello, Jamie Tayar, Timothy R. White, Kuldeep Verma, Mathieu Vrard, M. Yıldız, David Baker, Michaël Bazot, Charles Beichmann, Christoph Bergmann, Lisa Bugnet
The Astronomical Journal, Uluslararası, Wos, 2019, cilt 157, ss 245-245
Özet
Abstract We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite ( TESS ) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright ( V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 μ Hz 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 ( R ⋆ = 2.943 ± 0.064 R ⊙ ), mass ( M ⋆ = 1.212 ± 0.074 M ⊙ ), 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” ( R p = 9.17 ± 0.33 R ⊕ ) with an orbital period of ∼14.3 days, irradiance of F = 343 ± 24 F ⊕ , and moderate mass ( M p = 60.5 ± 5.7 M ⊕ ) and density ( ρ p = 0.431 ± 0.062 g cm −3 ). The properties of HD 221416 b show that the host-star metallicity–planet mass correlation found in sub-Saturns (4–8 R ⊕ ) 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%, HD 221416 b is one of the best characterized Saturn-size 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.