| Abstract |
Recent cosmochemical studies have shown that most of Earth’s building blocks were close to enstatite meteorites in isotopic compositions. This implies the formation of an impact-induced proto-atmosphere enriched in H2 and CH4 on accreting Earth. Such a reduced atmosphere may have played an important role in the prebiotic chemical evolution since the efficient synthesis of organic matter could be expected. On the other hand, the reduced atmosphere is expected to have changed with time through hydrodynamic escape induced by the strong XUV irradiation from the young Sun and photochemical reactions of reduced chemical species. In this talk, I will mainly show the results of our hydrodynamic escape simulations and a possible scenario of the early Earth’s atmosphere estimated by the calculation results. I will also talk about the comparison with the atmospheric escape of an early Martian atmosphere and the application to the atmospheric escape of exoplanets if I have time to spare. |
