Photoevaporation and High-Eccentricity Migration Created the Sub-Jovian Desert

TL;DR

The paper explains the origin of the sub-Jovian desert in exoplanet distributions through photoevaporation of sub-Neptunes and tidal disruption barriers affecting high-eccentricity migration of gas giants.

Contribution

It provides a unified explanation for the sub-Jovian desert shape by combining photoevaporation effects and tidal disruption constraints on migrating gas giants.

Findings

Photoevaporation is more effective closer to the star.

Tidal disruption limits the inward migration of gas giants.

Super-Earths and hot Jupiters have different formation histories.

Abstract

The mass-period or radius-period distribution of close-in exoplanets shows a paucity of intermediate mass/size (sub-Jovian) planets with periods ~< 3 days. We show that this sub-Jovian desert can be explained by the photoevaporation of highly irradiated sub-Neptunes and the tidal disruption barrier for gas giants undergoing high-eccentricity migration. The distinctive triangular shape of the sub-Jovain desert result from the fact that photoevaporation is more effective closer to the host star, and that in order for a gas giant to tidally circularise closer to the star without tidal disruption it needs to be more massive. Our work indicates that super-Earths/mini-Neptunes and hot-Jupiters had distinctly separate formation channels and arrived at their present locations at different times.