“Interpreting Terrestrial Exo-Atmospheres with JWST: Insights from Solar System Science”

We will soon have the technological capability to measure the atmospheric composition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In order to understand the degree to which we will learn of terrestrial planets from their atmospheres, I use the mystery of early Mars as a case study. I describe how we leverage models to learn of Mars’ ancient past, and make the case that this will be a very similar problem to the characterization of terrestrial planets with JWST. Then, I lay the framework for an information content-based approach to optimize our observations and maximize the retrievable information from exo-atmospheres. Lastly, I'll address what constraints on retrievable parameters we can expect to get from temperate, high-mean-molecular weight atmospheres, and specifically what this will tell us of the physical nature of their atmospheres.