Investigating the Planet-Metallicity Correlation for Hot Jupiters

TL;DR

This study analyzes the relationship between host star metallicity and hot Jupiter occurrence, finding a preference for metal-rich stars and suggesting similar formation processes to other gas giants with different migration histories.

Contribution

It provides a homogeneous, unbiased analysis of hot Jupiter metallicity correlation, comparing it with field stars and other gas giants, highlighting similarities in formation.

Findings

Hot Jupiters favor metal-rich stars.

Correlation is slightly weaker for hot Jupiters than longer period gas giants.

Hot Jupiters likely share formation processes with other gas giants.

Abstract

We investigate the giant planet-metallicity correlation for a homogeneous, unbiased set of 217 hot Jupiters taken from nearly 15 years of wide-field ground-based surveys. We compare the host star metallicity to that of field stars using the Besan\c{c}on Galaxy model, allowing for a metallicity measurement offset between the two sets. We find that hot Jupiters preferentially orbit metal rich stars. However, we find the correlation consistent, though marginally weaker, for hot Jupiters ($\beta=0.71^{+0.56}_{-0.34}$) than it is for other longer period gas giant planets from radial velocity surveys. This suggests that the population of hot Jupiters probably formed in a similar process to other gas giant planets, and differ only in their migration histories.