## Document Type

Article

## Publication Date

12-1-2021

## Published In

The Astronomical Journal

## Abstract

We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it transited the secondary star. The binary is itself eclipsing, with a period *P* ≈ 19.7 days and an eccentricity *e* ≈ 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of *M*_{1} = 1.2384 ±0.0007 *M*_{⊙} and *R*_{1} = 1.3827 ± 0.0016 *R*_{⊙} for the primary and *M*_{2} = 1.2019 ± 0.0007 *M*_{⊙} and *R*_{2} = 1.3124 ±0.0012 *R*_{⊙} for the secondary. The radius of the planet is *R*_{3} = 11.25 ± 0.44 *R*_{⊕} (1.004 ± 0.039*R*_{Jup}). The planet's mass and orbital properties are not uniquely determined—there are six solutions with nearly equal likelihood. Specifically, we find that the planet's mass is in the range of 824 ≲ *M*_{3} ≲ 981 *M*_{⊕} (2.65 ≲ *M*_{3} ≲ 3.09*M*_{Jup}), its orbital period could be 188.8, 190.4, 194.0, 199.0, 200.4, or 204.1 days, and the eccentricity is between 0.02 and 0.09. At *V* = 10.141 mag, the system is accessible for high-resolution spectroscopic observations, e.g., the Rossiter–McLaughlin effect and transit spectroscopy.

## Recommended Citation

V. B. Kostov et al.
(2021).
"TIC 172900988: A Transiting Circumbinary Planet Detected In One Sector Of TESS Data".
*The Astronomical Journal*.
Volume 162,
Issue 6.
DOI: 10.3847/1538-3881/ac223a

https://works.swarthmore.edu/fac-physics/485

## Comments

This work is a preprint that is freely available courtesy of IOP Publishing and the American Astronomical Society. The final published version is available online.