Demographics of Close-In TESS Exoplanets Orbiting FGK Main-sequence Stars

Abstract

Understanding the demographics of close-in planets is crucial for insights into exoplanet formation and evolution. We present a detailed analysis of occurrence rates for close-in (0.5-16 day) planets with radii between 2 and 20$R_{\oplus }$ around FGK main-sequence stars. Our study uses a comprehensive sample from four years of TESS Science Processing Operations Center full-frame image data cross-matched with Gaia, analysed through our rigorous detection, vetting, and validation pipeline. Using high-confidence planet candidates, we apply a hierarchical Bayesian model to determine occurrence rates in the two-dimensional orbital period-radius plane. Our results are presented using 10-by-10 bins across the period-radius parameter space, offering unprecedented resolution and statistical precision. We find an overall occurrence rate of $9.4_{-0.6}^{+0.7}\%$. When using identical binning, our occurrence rate posteriors distributions align with Kepler's but have a magnitude smaller uncertainties on average. For hot Jupiters, we estimate the overall occurrence rate of $0.39_{-0.02}^{+0.03}\%$. This value is consistent with the previous Kepler FGK-type result within $1\ddot{I}ƒ$. We find an overall occurrence rate of Neptunian desert planets of $0.08\pm 0.01\%$, to our knowledge the first such determination. Additionally, in a volume-limited Gaia subsample within 100 pc in the same parameter region, we measure an overall planet occurrence rate of $15.4_{-1.5}^{+1.6}\%$ and a hot Jupiter occurrence rate of $0.42_{-0.12}^{+0.16}\%$. Our results establishes an improved foundation for constraining theoretical models of exoplanet populations.

16 pages, 16 figures, 2 tables, accepted for publication in MNRAS. Online interactive TESS occurrence rate: https://cuikaiming.com/TESS-SPOC-Occurrence-Rate/