Abstract

Super-Earths and sub-Neptunes are the most abundant exoplanets discovered in our galaxy to date. However, much of their nature and origin remains shrouded in mystery. Generally speaking, super-Earths and sub-Neptunes are thought to have formed as one population with primordial hydrogen-dominated envelopes. However, most super-Earths lost their primordial atmospheres via thermally driven winds. In my talk, I will present global chemical equilibrium models of Earth, super-Earths and sub-Neptunes. I will show that magma-ocean atmosphere interactions expected in sub-Neptunes exoplanets lead to signatures in their transmission spectra that are readily observable with JWST . In addition, hydrogen is efficiently sequestered into the interior, oxidizing iron and endogenously producing water. I will conclude by discussing possible parallels between Earth’s formation and that of super-Earths, shedding new light on Earth’s primary water reservoir, origin of the light elements in its iron core and oxidation state.