The Diversity of Extrasolar Terrestrial Planets

TL;DR

This study combines dynamical and chemical models to predict the diverse bulk compositions of terrestrial planets in extrasolar systems, revealing a wide range of possible planetary types beyond Earth-like compositions.

Contribution

It introduces a novel integrated modeling approach to constrain the bulk compositions of extrasolar terrestrial planets, highlighting their potential diversity.

Findings

Planetary compositions range from Earth-like to graphite and SiC dominated.

Extrasolar terrestrial planets exhibit a wide variety of bulk elemental compositions.

Diversity in planetary building blocks suggests many different types of terrestrial planets exist.

Abstract

Extrasolar planetary host stars are enriched in key planet-building elements. These enrichments have the potential to drastically alter the building blocks 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 constrain the bulk elemental composition of extrasolar terrestrial planets. A wide variety of resulting planetary compositions exist, ranging from those that are essentially "Earth-like", containing metallic Fe and Mg-silicates, to those that are dominated by graphite and SiC. This implies that a diverse range of terrestrial planets are likely to exist within extrasolar planetary systems.