Coupling the inflated interiors and the atmospheric dynamics of hot Jupiters

Hot Jupiters are the best characterized class of exoplanet, yet significant mysteries remain concerning the chemistry and dynamics of their atmospheres and the evolution of their interiors. We propose to attack these problems by more self-consistently modeling the inherent coupling between the interiors and 3D atmospheres of hot Jupiters. Importantly, the atmospheres of gas giant exoplanets are in reality thin boundary layers that contain only 0.01% of the mass of the planet, yet determine the rate at which the interior of hot Jupiters can cool to space.

The radius distribution of discovered hot Jupiters encompasses many planets with radii larger than expected based on standard models of stellar irradiation and planetary cooling. This so-called "inflation problem" may imply that a mechanism transports heat from the atmosphere into the interior of the planet, as suggested from recent deep-atmosphere general circulation models (GCMs).

However, previous work has not interwoven the expectations from atmospheric GCMs with model predictions for the interior evolution of hot Jupiters.

The primary objective of this work is to determine how the coupling between the atmospheric circulation and interior evolution affects both the observable properties of the atmospheres of hot Jupiters and their radius evolution. To do so, we will investigate the internal evolution of highly irradiated gas giants by upgrading the Modules for Experiments in Stellar Astrophysics (MESA) planetary evolution code to include a compressible core in collaboration with Andrew Youdin at the University of Arizona.

We will conduct a suite of MESA evolutionary models of hot Jupiters to determine the combination of the amount of internal heating and the depth of that heating needed to match the observed sample of hot Jupiters. We will then conduct a suite of three-dimensional models of the atmospheric dynamics of hot Jupiters using the MITgcm. These models will be driven with the deep atmospheric temperature structure predicted from the larger grid of MESA evolutionary models to determine how the internal evolution of hot Jupiters affects their shallower atmospheric circulation.

Lastly, we will apply our MESA-MITgcm framework to specific well-studied Jupiters in order to test predictions for the mechanisms that lead to the radius inflation of hot Jupiters. We will use the combination of atmospheric and evolutionary information in order to test predictions for the mechanisms that lead to the radius inflation of hot and ultra-hot Jupiters, impacting the broader exoplanet community.

This project falls within the EPSRC physical sciences research theme, as it focuses on understanding the physics underpinning planetary atmospheres.