Abstract

At present, we only understand how terrestrial planet atmospheres evolve around the Sun. In order to understand the atmospheres of terrestrial exoplanets with diverse compositions and formation pathways, we need robust models which can track how atmospheres change over billions of years. Studies of the Earth’s interior have allowed geoscientists to understand the thermal evolution of planet interiors and the outgassing of CO2, while studies of high-energy radiation from stars have revealed the dangerous conditions for which atmospheric elements can be stripped from planets. In this talk, I will discuss our plan to integrate the most up-to-date models from both of these research areas into a simulation package that evolves terrestrial planet atmospheres by volatile outgassing and atmospheric escape. I will describe the details of our existing and developing models of interior thermal evolution, stellar XUV radiation, and atmospheric escape. We will use our package to simulate and constrain the evolution of terrestrial planet atmospheres orbiting low-mass M dwarf stars; the only stars for which atmospheric characterization of terrestrial exoplanets will be possible in the near-term with the James Webb Space Telescope (JWST) and the next generation of ground-based extremely large telescopes. I will present preliminary results of atmospheric evolution for LHS 3844b, a terrestrial planet planned for observation by JWST in its first cycle. Finally, I will briefly discuss our plans to develop our package to model not only hot, CO2-dominated atmospheres but also potentially habitable atmospheres.