A Bayesian approach shows no correlation between transit-depth and stellar metallicity for confirmed and candidates Kepler gas giants planets

Abstract

Previous study to investigate the correlation between the transit depth and the stellar metallicity of Kepler’s (Q1-Q12) gas giant planets (radii of 5-20R_⊙) has led to a weakly significant negative correlation. We use the cumulative catalog of planets detected by the NASA Kepler mission Q1-Q17 catalog, as of April 2015, to perform a solid statistical analysis of this correlation. In the present work, we revise this correlation, within a Bayesian framework, for two large samples: sample A confirmed planets and sample B (confirmed + candidates). We expand a hierarchical method to account for false positives in the studied samples. Our statistical analysis reveals no correlation between the transit depth and the stellar metallicity. This has implications for planet formation theory and interior structure of giant planets.