Speaker: Aaron Werlen
Affiliation: EPSS, UCLA
Date: Wednesday, May 20, 2026
Time: 12:00 PM
Abstract
Atmospheric compositions of sub-Neptunes and super-Earths are often interpreted as tracers of formation history and volatile delivery. However, many of these planets likely experience long-lived magma-ocean phases during which their atmospheres can chemically equilibrate with a molten silicate interior. In this talk, I will show how magma-ocean–atmosphere interactions reshape atmospheric compositions and alter observable signatures. Using a global chemical equilibrium framework, I demonstrate that key abundance ratios such as C/O and H2O are not simply inherited from disk accretion, but can be substantially modified by interior processing. This has important implications for the interpretation of apparently water-rich worlds, which may in fact be significantly drier than predicted by previous models. I will also present new extensions of the model including sulfur and nitrogen chemistry, which provide additional diagnostics of volatile redistribution between atmosphere and interior and further strengthen the connection between interior evolution, atmospheric composition, and spectroscopic observations.