A Short History of (Orbital) Decay: Roman's Prospects for Detecting Dying Planets

Abstract

The Roman Space Telescope Galactic Bulge Time Domain Survey (GBTDS) is expected to detect ~$10^5$ transiting planets. Many of these planets will have short orbital periods and are thus susceptible to tidal decay. We use a catalog of simulated transiting planet detections to predict the yield of orbital decay detections in the Roman GBTDS. Assuming a constant stellar tidal dissipation factor, $Q^{'}_{*}$, of $10^6$, we predict ~ 5 - 10 detections. We additionally consider an empirical period-dependent parameterization of $Q^{'}_{*} \propto P^{-3}$ and find a substantially suppressed yield. We conclude that Roman will provide constraints on the rate of planet engulfment in the Galaxy and probe the physics of tidal dissipation in stars.