The Enigmatic Atmospheres of Rocky Planets
Dr. Michael Zhang
Inaugural E. Margaret Burbidge Prize Postdoctoral Fellow
Astronomy and Astrophysics
University of Chicago
Among the thousands of exotic exoplanets that have been discovered over the past two decades, the predominantly rocky planets remind us tantalizingly—perhaps wrongly—of Earth. The Earth-sized rocky planets orbiting M dwarfs are our only realistic chance of detecting life in the near future—if their temperamental hosts have not already stripped them of their atmospheres. With JWST observations of the thermal emission of five M dwarf rocky planets at different temperatures, we determine which planets (if any) still retain atmospheres and which ones do not. Moving on from these Earth-sized worlds, I will focus on their larger cousins, the mini-Neptunes: low-density planets which may be either water worlds, or rocky planets with a 1-2% H/He atmosphere. By observing their escaping atmospheres in the 1083 nm helium line, we can distinguish between these two possibilities. We will also be able to test a long-standing hypothesis: do the larger, puffier mini-Neptunes become the smaller, denser super-Earths by losing their thick (~10^5 bar) atmospheres?
Hosted by Prof. Weiss