2020/04/16 by Veselin B. Kostov, Jerome A. Orosz, Adina D. Feinstein +65 · 1 citation
Physics and Astronomy · #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/ab8a48
35 pages, 21 figures, 6 tables
arxiv created 2020/04/16 · arxiv updated 2020/05/13
We report the detection of the first circumbinary planet found by 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 two-minute cadence. It consists of two stars with masses of 1.1 MSun and 0.3 MSun 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 REarth 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 circumbinary planets. 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 degree. 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 circumbinary planets, and provides further understanding of the formation and evolution of planets orbiting close binary stars.