The Compositional Diversity of Extrasolar Terrestrial Planets: I. In-Situ Simulations

TL;DR

This study combines dynamical and chemical models to simulate the composition of terrestrial planets in extrasolar systems, revealing a wide diversity from Earth-like to carbon-rich planets.

Contribution

It introduces a novel approach integrating dynamical formation models with chemical equilibrium calculations to predict planetary compositions.

Findings

Planetary compositions vary widely, from Earth-like to graphite and SiC dominated.

Extrasolar host star element enrichments significantly influence planet composition.

Diverse terrestrial planets can form in known extrasolar systems.

Abstract

Extrasolar planet host stars have been found to be enriched in key planet-building elements. These enrichments have the potential to drastically alter the composition of material available for terrestrial planet formation. Here we report on the combination of dynamical models of late-stage terrestrial planet formation within known extrasolar planetary systems with chemical equilibrium models of the composition of solid material within the disk. This allows us to determine the bulk elemental composition of simulated extrasolar terrestrial planets. A wide variety of resulting planetary compositions are found, ranging from those that are essentially "Earth-like", containing metallic Fe and Mg-silicates, to those that are dominated by graphite and SiC. This shows that a diverse range of terrestrial planets may exist within extrasolar planetary systems.