The First Circumbinary Planet Discovered by TESS
Abstract
We report the discovery of the first circumbinary planet from TESS. The target was observed in sectors 1 through 12 in Full-Frame Images at 30-minute cadence and in sectors 4 through 12 at two-minute cadence. The host eclipsing binary consists of two stars with masses of 1.1 and 0.3 MSun on a slightly eccentric (0.16), 14.6-day orbit. The small mass ratio results in prominent primary eclipses and shallow secondary eclipses. The planet produced three transits across the primary star of roughly constant 0.2% depth but different durations, a common signature of transiting circumbinary planets caused by the variable relative motion between the star and planet. The planet's period is roughly 95 days with negligible eccentricity and the orbit is aligned to within 2 degrees of the binary's orbital plane. We combined the precise photometry from TESS with ground-based radial-velocity observations in a numerical photo-dynamical model. The system demonstrates the discovery potential of TESS for circumbinary planets, and provides further understanding of the formation and evolution of planets orbiting close binary stars.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23534905K