Giant Planet Evolution with MESA

TL;DR

This paper enhances the MESA code with new physics modules and modifications to better simulate the evolution of gaseous giant planets, including improved equations of state, opacities, and mixing processes.

Contribution

The paper introduces specific modifications to MESA, such as tailored equations of state and improved convective and helium rain treatments, to advance giant planet modeling capabilities.

Findings

Enhanced MESA code with new physics modules for giant planets

Improved accuracy in internal structure calculations

Public availability of the modified code

Abstract

The evolution of gaseous planets is a complex process influenced by various physical parameters and processes. In this study, we present critical modifications to the Modules for Experiments in Stellar Astrophysics (MESA) code to enhance its applicability to giant planet modelling. We introduce an equation of state specifically tailored for materials at planetary conditions. The equation of state considers the thermodynamic properties of hydrogen-helium mixtures and heavy elements, improving the accuracy of internal structure calculations. We also present modifications to the radiative opacity to allow the modelling of grains, clouds and opacity windows. Furthermore, we refine the treatment of convective mixing processes in MESA to better replicate convective mixing with the presence of composition gradients. Finally, we add a treatment for helium rain and settling. These modifications aim to enhance the predictive capabilities of MESA for giant planet evolution and are publicly available. We hope that these improvements will lead to a deeper understanding of giant planet evolution in the solar system and beyond.