Early Evolution of Super-Earths: From Magma Ocean to Temperate Surface Conditions

Recent discoveries of potentially temperate rocky planets motivate the better characterization of their surface conditions to predict where life could be detected in the universe. Early habitability of rocky planets is determined by the cooling and solidification of the magma ocean (MO) stage. Indeed, the initial volatile content in the MO and the distance from the host star appear to play key-roles in the solidification of the MO, the extraction of the atmosphere, the existence of clouds and the formation (or not) of a primitive water ocean. However, the atmospheric properties strongly influence the planetary albedo, and therefore the amount of sunlight reaching the planet surface. This in turn acts on the cooling rate of the planet and its atmosphere degassing. Using a coupled 1-D MO-atmosphere model, we systematically studied how the feedback between albedo, atmospheric composition, planetary surface temperature and clouds, influences the formation of a water ocean at the end of the initial rapid cooling stage of the planet. Here we extend this approach to different MO scenarios for super-Earths (ratio of planetary to core radius, volatile delivery) and discuss their potential habitability at the end of the rapid cooling stage.