Bibcode
Huber, Daniel; Chaplin, William J.; Chontos, Ashley; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen; Bedding, Timothy R.; Ball, Warrick; Brahm, Rafael; Espinoza, Nestor; Henning, Thomas; Jordán, Andrés; Sarkis, Paula; Knudstrup, Emil; Albrecht, Simon; Grundahl, Frank; Fredslund Andersen, Mads; Pallé, Pere L.; Crossfield, Ian; Fulton, Benjamin; Howard, Andrew W.; Isaacson, Howard T.; Weiss, Lauren M.; Handberg, Rasmus; Lund, Mikkel N.; Serenelli, Aldo M.; Rørsted Mosumgaard, Jakob; Stokholm, Amalie; Bieryla, Allyson; Buchhave, Lars A.; Latham, David W.; Quinn, Samuel N.; Gaidos, Eric; Hirano, Teruyuki; Ricker, George R.; Vanderspek, Roland K.; Seager, Sara; Jenkins, Jon M.; Winn, Joshua N.; Antia, H. M.; Appourchaux, Thierry; Basu, Sarbani; Bell, Keaton J.; Benomar, Othman; Bonanno, Alfio; Buzasi, Derek L.; Campante, Tiago L.; Çelik Orhan, Z.; Corsaro, Enrico; Cunha, Margarida S.; Davies, Guy R.; Deheuvels, Sebastien; Grunblatt, Samuel K.; Hasanzadeh, Amir; Di Mauro, Maria Pia; García, Rafael A.; Gaulme, Patrick; Girardi, Léo; Guzik, Joyce A.; Hon, Marc; Jiang, Chen; Kallinger, Thomas; Kawaler, Steven D.; Kuszlewicz, James S.; Lebreton, Yveline; Li, Tanda; Lucas, Miles; Lundkvist, Mia S.; Mann, Andrew W.; Mathis, Stéphane; Mathur, Savita; Mazumdar, Anwesh; Metcalfe, Travis S.; Miglio, Andrea; Monteiro, Mário J. P. F. G.; Mosser, Benoit; Noll, Anthony; Nsamba, Benard; Ong, Jia Mian Joel; Örtel, S.; Pereira, Filipe; Ranadive, Pritesh; Régulo, Clara; Rodrigues, Thaíse S.; Roxburgh, Ian W.; Silva Aguirre, Victor; Smalley, Barry; Schofield, Mathew; Sousa, Sérgio G.; Stassun, Keivan G.; Stello, Dennis; Tayar, Jamie; White, Timothy R.; Verma, Kuldeep; Vrard, Mathieu; Yıldız, M.; Baker, David; Bazot, Michaël; Beichmann, Charles; Bergmann, Christoph; Bugnet, Lisa et al.
Bibliographical reference
The Astronomical Journal, Volume 157, Issue 6, article id. 245, 14 pp. (2019).
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6
2019
Citations
81
Refereed citations
71
Description
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 μHz
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.
Related projects
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary
Savita
Mathur