LPL Colloquium: Dr. Stéphane Mazevet
Coupling Planetary and Ecosystem Modeling to Assess Habitability and Inhabitation in the Solar System and Beyond
Dr. Stéphane Mazevet
Côte d'Azur Observatory
With thousands of exoplanets now identified, the characterization of habitable planets and the potential identification of inhabited ones is a major challenge for the coming decades. To address this challenge, we developed an innovative approach to assess habitability and inhabitation by coupling for the first time the atmosphere and the interior modeling with the biological activity based on ecosystem modeling. I will review the results we obtained in four different situations where habitability and inhabitation are in question. We first applied the method to asses the possibility of methanogenic activity at the Enceladus ocean floor and provide an interpretation for the plume composition measured by the Cassini mission. Secondly, we quantified the impact of methanogenic activity on the composition of the early Earth atmosphere and its influence on the long term climate. Thirdly, we considered Early Mars to asses favorable landing sites to investigate whether methanogenesis started 4 billion years ago. Lastly, we applied the method to habitable Earth-like planets around G-type stars to inform the design of future space missions.
 A. Affholder, F. Guyot, B. Sauterey, R. Ferrière, S. Mazevet, Bayesian analysis of Enceladus’s plume data to assess methanogenesis, Nature Astronomy 5 (2021), p. 805-814.
 B. Sauterey, B. Charnay, A. Affholder, S. Mazevet, R.F errière, Co-evolution of primitive methane-cycling ecosystems and early Earth’s atmosphere and climate, Nature Communications 11 (2020).
 B. Sauterey, B. Charnay, A. Affholder, S. Mazevet, R. Ferrière, Early Mars habitability and global cooling by H2-based methanogens, Nature Astronomy (2022).
 S. Mazevet, A. Affholder, B. Sauterey, A. Bixel, D. Apai and R. Ferriere, Prospects for the characterization of habitable planets, accepted (2023).
Host: Dr. Daniel Apai