Effects of Self-gravity on Mass-loss of the Post-impact Super-Earths

TL;DR

This study investigates how self-gravity influences atmospheric mass loss in post-impact super-Earths, revealing that self-gravity can significantly alter the impact-driven atmospheric escape process and the resulting planetary structure.

Contribution

It demonstrates the crucial role of self-gravity in affecting mass-loss efficiency and planetary envelope retention after giant impacts.

Findings

Self-gravity shifts the radiative-convective boundary inward.

Including self-gravity increases the impactor mass needed for significant mass loss.

Self-gravity becomes more important as envelope mass and temperature increase.

Abstract

Kepler's observations show most of the exoplanets are super-Earths. The formation of super-Earth is generally related to the atmospheric mass loss that is crucial in the planetary structure and evolution. The shock driven by the giant impact will heat the planet, resulting in the atmosphere escape. We focus on whether self-gravity changes the efficiency of mass loss. Without self-gravity, if the impactor mass is comparable to the envelope mass, there is a significant mass-loss. The radiative-convective boundary will shift inward by self-gravity. As the temperature and envelope mass increase, the situation becomes more prominent, resulting in a heavier envelope. Therefore, the impactor mass will increase to motivate the significant mass loss, as the self-gravity is included. With the increase of envelope mass, the self-gravity is particularly important.