Inflated Eccentric Migration of evolving gas giants II: Numerical methodology and basic concepts

TL;DR

This study investigates how the thermal evolution and potential re-inflation of gas giants influence their eccentric migration, revealing faster migration timescales and higher occurrence rates of hot and warm Jupiters compared to previous models.

Contribution

It introduces a detailed numerical model coupling thermal and orbital evolution of gas giants, highlighting the impact of planetary inflation on migration timescales and occurrence rates.

Findings

Inflated gas giants migrate faster than previously thought.

Higher occurrence rates of warm Jupiters are predicted.

More tidal disruptions occur due to rapid migration.

Abstract

Hot and Warm Jupiters (HJs&WJs) are gas-giant planets orbiting their host stars at short orbital periods, posing a challenge to their efficient in-situ formation. Therefore, most of the HJs&WJs are thought to have migrated from an initially farther-out birth locations. Current migration models, i.e disc-migration (gas-dissipation driven) and eccentric-migration (tidal evolution driven), fail to produce the occurrence rate and orbital properties of HJs&WJs. Here we study the role of the thermal evolution and its coupling to tidal evolution. We use the AMUSE, numerical environment, and MESA, planetary evolution modeling, to model in detail the coupled internal and orbital evolution of gas-giants during their eccentric-migration. In a companion paper, we use a simple semi-analytic model, validated by our numerical model, and run a population-synthesis study. We consider the initially inflated radii of gas-giants (expected following their formation), as well study the effects of the potential slowed contraction and even re-inflation of gas-giants (due to tidal and radiative heating) on the eccentric-migration. Tidal forces that drive eccentric-migration are highly sensitive to the planetary structure and radius. Consequently, we find that this form of inflated eccentric-migration operates on significantly (up to an order of magnitude) shorter timescales than previously studied eccentric-migration models. Thereby, inflated eccentric-migration gives rise to more rapid formation of HJs&WJs, higher occurrence rates of WJs, and higher rates of tidal disruptions, compared with previous eccentric migration models which consider constant ~Jupiter radii for HJ&WJ progenitors. Coupled thermal-dynamical evolution of eccentric gas-giants can therefore play a key-role in their evolution.