报告简介：

Considerations of a planet's habitability to life typically center on the presence of liquid water, but chemistry is no less essential. New population-level studies that couple atmospheres to interiors allow us to predict planetary chemical evolution in unprecedented detail. Our models produce an atmospheric ‘oxidation gradient’ across the exoplanet radius valley, with He, CO, CO2 and in some cases O2-dominated atmospheres predicted on rocky planets that began life as much larger sub-Neptunes. Atmospheric loss is driven by escape to space but collapse of volatiles in nightside cold traps also plays a critical, under-appreciated role. Exciting new data on rocky exoplanet atmospheres and surfaces are now emerging, including the recent discovery of helium escaping from the super-Earth LHS 1140b. Back in the solar system, the fluctuating chemistry of Mars is recorded in the rock record and may also be tied to the planet’s dynamic early habitability. Mars sample return is required to link this record to the state of the early atmosphere and the potential for prebiotic chemistry.

主讲人简介：

Robin Wordsworth is a planetary scientist and Gordon McKay Professor in the School of Engineering and Applied Sciences at Harvard University. His work focuses on the physics and chemistry of rocky planets. His research interests include the climates of early Mars and Venus, sub-Neptunes and rocky exoplanets, and the coupling between CO2, climate and glaciation on Earth over time. Recently, his work has also extended to the question of how astrobiology can aid human space exploration. Recognition for Robin's work includes an NSF CAREER award and inclusion on the 2022 SN10 Scientists to Watch list.