TOI-1338: TESS' First Transiting Circumbinary Planet

Veselin B. Kostov , Jerome A. Orosz , Adina D. Feinstein , William F. Welsh , Wolf Cukier , Nader Haghighipour , Billy Quarles , David V. Martin , Benjamin T. Montet , Guillermo Torres , Amaury H. M. J. Triaud , Thomas Barclay , Patricia Boyd , Cesar Briceno , Andrew Collier Cameron , Alexandre C. M. Correia , Emily A. Gilbert , Samuel Gill , Michaël Gillon , Jacob Haqq-Misra , Coel Hellier , Courtney Dressing , Daniel C. Fabrycky , Gabor Furesz , Jon M. Jenkins , Stephen R. Kane , Ravi Kopparapu , Vedad Kunovac Hodžić , David W. Latham , Nicholas Law , Alan M. Levine , Gongjie Li , Chris Lintott , Jack J. Lissauer , Andrew W. Mann , Tsevi Mazeh , Rosemary Mardling , Pierre F. L. Maxted , Nora Eisner , Francesco Pepe , Joshua Pepper , Don Pollacco , Samuel N. Quinn , Elisa V. Quintana , Jason F. Rowe , George Ricker , Mark E. Rose , S. Seager , Alexandre Santerne (1) , Damien Ségransan , Donald R. Short , Jeffrey C. Smith , Matthew R. Standing , Andrei Tokovinin , Trifon Trifonov , Oliver Turner , Joseph D. Twicken , Stéphane Udry , Roland Vanderspek , Joshua N. Winn , Eric T. Wolf , Carl Ziegler , Peter Ansorge , Frank Barnet , Joel Bergeron , Marc Huten , Giuseppe Pappa , Timo van Der Straeten

1 LAM - Laboratoire d'Astrophysique de Marseille

We report the detection of the first circumbinary planet (CBP) found by Transiting Exoplanet Survey Satellite (TESS). The target, a known eclipsing binary, was observed in sectors 1 through 12 at 30 minute cadence and in sectors 4 through 12 at 2 minute cadence. It consists of two stars with masses of 1.1 M_⊙ and 0.3 M_⊙ on a slightly eccentric (0.16), 14.6 day orbit, producing prominent primary eclipses and shallow secondary eclipses. The planet has a radius of ∼6.9 R_⊕ and was observed to make three transits across the primary star of roughly equal depths (∼0.2%) but different durations—a common signature of transiting CBPs. Its orbit is nearly circular (e ≍ 0.09) with an orbital period of 95.2 days. The orbital planes of the binary and the planet are aligned to within ∼1°. To obtain a complete solution for the system, we combined the TESS photometry with existing ground-based radial-velocity observations in a numerical photometric-dynamical model. The system demonstrates the discovery potential of TESS for CBPs and provides further understanding of the formation and evolution of planets orbiting close binary stars.

Keywords: Exoplanet astronomy; Eclipsing binary stars; 486; 444; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics

Domains: Sciences of the Universe [physics]

Veselin B. Kostov, Jerome A. Orosz, Adina D. Feinstein, William F. Welsh, Wolf Cukier, et al.. TOI-1338: TESS' First Transiting Circumbinary Planet. The Astronomical Journal, 2020, 159, ⟨10.3847/1538-3881/ab8a48⟩. ⟨insu-03667098⟩