LPL Colloquium: Dr. Sukrit Ranjan

Theoretical Underpinnings of the Search for Life on Exoplanets
Dr. Sukrit Ranjan
Prize Postdoctoral Fellow
Center for Interdisciplinary Exploration and Research in Astrophysics
Department of Physics & Astronomy
Northwestern University
We are on the cusp of a revolution in our understanding of life in the universe. Exoplanet surveys like Kepler have revealed potentially habitable planets to be common, and upcoming facilities like the James Webb Space Telescope and the Thirty Meter Telescope will at last have the ability to characterize their atmospheres in search of signs of life. However, proceeding from the astrophysical observables to inferences regarding the presence or absence of life will require considerable theoretical intervention. In this talk, I will illustrate the theoretical infrastructure that must be developed to prepare for exoplanet life search with three vignettes. Specifically, I will discuss (1) the UV environment on planets orbiting M-dwarfs and the implications for their inhabitability, (2) the photochemistry of water vapor and the implications for oxygen as a biosignature gas on planets orbiting Sun-like stars, and (3) efforts to increase the catalog of potential remote biomarkers of life, with a focus on reactive gases like phosphine. I will conclude by reviewing the considerable theoretical and laboratory work that remains to be done to prepare for the era of habitable planet characterization.


Thursday, December 2, 2021 - 3:45pm