Age distribution of exoplanet host stars: Chemical and Kinematics age proxies from GAIA DR3

TL;DR

This study uses Gaia DR3 data to analyze the chemical and kinematic properties of exoplanet host stars, revealing age-related differences between hosts of small and giant planets through chemical composition, orbital parameters, and stellar ages.

Contribution

It provides a comprehensive analysis combining chemical, kinematic, and age proxies for a large sample of exoplanet host stars using Gaia DR3 data, highlighting differences based on planet size.

Findings

Stars hosting massive planets are metal-rich and alpha-poor.

Stars with small and giant planets differ in galactic orbital parameters.

Giant planet hosts tend to be younger than small planet hosts.

Abstract

The GAIA space mission is impacting astronomy in many significant ways by providing a uniform, homogeneous and precise data set for over 1 billion stars and other celestial objects in the Milky Way and beyond. Exoplanet science has greatly benefited from the unprecedented accuracy of stellar parameters obtained from GAIA. In this study, we combine photometric, astrometric, and spectroscopic data from the most recent Gaia DR3 to examine the kinematic and chemical age proxies for a large sample of 2611 exoplanets hosting stars whose parameters have been determined uniformly. Using spectroscopic data from the Radial Velocity Spectrometer (RVS) onboard GAIA, we show that stars hosting massive planets are metal-rich and $\alpha$-poor in comparison to stars hosting small planets. The kinematic analysis of the sample reveals that the stellar systems with small planets and those with giant planets differ in key aspects of galactic space velocity and orbital parameters, which are indicative of age. We find that the galactic orbital parameters have a statistically significant difference of 0.06 kpc for $Z_{max}$ and 0.03 for eccentricity respectively. Furthermore, we estimated the stellar ages of the sample using the MIST-MESA isochrone models. The ages and its proxies for the planet-hosting stars indicate that the hosts of giant planetary systems are younger compared to the population of stars harboring small planets. These age trends are also consistent with the chemical evolution of the galaxy and the formation of giant planets from the core-accretion process.