Abstract

With the successful deployment of JWST, and its aim to potentially search for biosignatures on exoplanets, an important endeavor, at present, is to determine whether the rocky planets we observe are likely to have atmospheres at all. M dwarfs, the main host stars of JWST’s rocky planet targets, are thought to pose a major threat to planetary atmospheres due to their high magnetic activity over several billion-year timescales, and might completely strip atmospheres. Several Cycle 1 GO programs are testing this hypothesis, observing some of the most interesting rocky planets that we know, e.g., those in the TRAPPIST-1 system. An interesting case-study is TRAPPIST-1c, which receives almost the same bolometric flux as Venus. We might, therefore, expect TRAPPIST-1c to possess a thick, CO2-dominated atmosphere. In this talk, I will present results from recent observations that constrain the size of TRAPPIST-1c's atmosphere. To interpret these results, I have developed and run coupled time-dependent simulations of planetary outgassing and atmospheric escape, processes that most influence atmospheres, to model the evolution of TRAPPIST-1c’s atmosphere. I will review the results of these simulations, specifically the constraints that they place on the history of TRAPPIST-1c’s atmospheric and geological properties. Finally, I will discuss the implications of these results for the other TRAPPIST-1 planets, and future developments that will help further characterize the evolution of their atmospheres.