Giant planet formation models with a self-consistent treatment of the heavy elements

TL;DR

This paper introduces a new numerical model for giant planet formation that self-consistently accounts for heavy-element dissolution and enrichment, impacting formation timescales, internal structure, and observable properties.

Contribution

It develops a self-consistent framework based on MESA to simulate giant planet formation with detailed heavy-element treatment, including dissolution and enrichment effects.

Findings

Heavy-element enrichment shortens formation timescales.

Runaway gas accretion rate influences planetary radius and luminosity.

Jupiter's formation can be consistent with disk lifetimes under certain enrichment conditions.

Abstract

We present a new numerical framework to model the formation and evolution of giant planets. The code is based on the further development of the stellar evolution toolkit Modules for Experiments in Stellar Astrophysics (MESA). The model includes the dissolution of the accreted planetesimals/pebbles, which are assumed to be made of water ice, in the planetary gaseous envelope, and the effect of envelope enrichment on the planetary growth and internal structure is computed self-consistently. We apply our simulations to Jupiter and investigate the impact of different heavy-element and gas accretion rates on its formation history. We show that the assumed runaway gas accretion rate significantly affect the planetary radius and luminosity. It is confirmed that heavy-element enrichment leads to shorter formation timescales due to more efficient gas accretion. We find that with heavy-element enrichment Jupiter's formation timescale is compatible with typical disks' lifetimes even when assuming a low heavy-element accretion rate (oligarchic regime). Finally, we provide an approximation for the heavy-element profile in the innermost part of the planet, providing a link between the internal structure and the planetary growth history.