Astrophysics Seminar with James Lyons on Isotopes in Atmospheres
The stable isotopes of H, C, N, O and S are invaluable tools for investigating a variety of atmospheric processes. For ancient Earth we use S isotopes as a proxy for the rise of atmospheric O2. For Venus and Mars we use H isotopes as a measure of the loss of water over time. In this talk, I will focus on N and S isotopes in the atmosphere of Earth, and, defining 'atmosphere' broadly, I will also discuss N isotopes in the solar nebula. I will present the talk in 3 parts. Part 1: An N2 self-shielding origin for the massive enrichment of 15N in the inner solar system: Yea or nay? Part 2: A laboratory experiment to explore N isotope fractionation in Earth's thermosphere. Part 3: Some thoughts on the origin of sulfur isotope fractionation on ancient Earth. By necessity, these topics will focus on one particular aspect of the problem, rather than a complete overview of each topic.
Sponsored by the McDonnell Center for the Space Sciences.