Effect of Galactic Chemical Evolution on Exoplanet Properties

TL;DR

This study models how galactic chemical evolution influences exoplanet composition, revealing that planets around older stars tend to have larger mantles and lower densities, aligning with observational data.

Contribution

It introduces a coupled model integrating galactic chemical evolution with planetary formation and structure modeling, highlighting the impact of element abundance changes over time.

Findings

Older star planets have larger mantles and lower densities.

Elemental abundance evolution affects planetary core size.

Results align with recent observational data.

Abstract

We couple a simplified model for the galactic chemical evolution, with software that models the condensation of dust in protoplanetary disks and software that models the interior structure of planets in order to estimate the effects that the galactic chemical evolution has on the properties of planets as they form over time. We find that the early abundance of elements formed from the evolution and death of high-mass stars (such as Oxygen, Silicon, and Magnesium) yields planets with larger mantles and smaller cores. The later addition of elements produced in low-mass stars (such as Iron and Nickel) causes the planet cores to become relatively larger. The result is planets that orbit older stars are less dense than planets orbiting younger stars. These results are broadly consistent with recent observations of planet properties from stars of varying ages.