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

TL;DR

This study provides a detailed, high-resolution analysis of the occurrence rates of close-in exoplanets around FGK main-sequence stars using four years of TESS data, offering insights into planet demographics and formation.

Contribution

It introduces a hierarchical Bayesian model applied to TESS data to produce high-resolution occurrence rate maps across the period-radius space, with improved statistical precision over previous surveys.

Findings

Overall occurrence rate of 9.4% for close-in planets.

Hot Jupiter occurrence rate of 0.39%.

First determination of Neptunian desert planet occurrence rate.

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 $9.4^{+0.7}_{-0.6}\%$. 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 $0.39^{+0.03}_{-0.02}\%$. This value is consistent with the previous Kepler FGK-type result within $1\sigma$. We find an overall occurrence rate of Neptunian desert planets of $0.08\pm0.01\%$, 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 $15.4^{+1.6}_{-1.5}\%$ and a hot Jupiter occurrence rate of $0.42^{+0.16}_{-0.12}\%$. Our results establishes an improved foundation for constraining theoretical models of exoplanet populations.