PHYS/ASTR Colloquium: "Monitoring Extrasolar Climate in 4D: Characterizing Brown Dwarf Atmospheres with HST and JWST" - Dr. Ben Lew (NASA AMES/BAERI)

Monitoring Extrasolar Climate in 4D: Characterizing Brown Dwarf Atmospheres with HST and JWST 

Ultracool brown dwarfs are substellar objects that share overlapping temperature and gravity ranges with exoplanets. Brown dwarfs are easier to study in detail than exoplanets, serving as excellent exoplanet analogs for studying the key physical and chemical processes in extrasolar planetary atmospheres. Observations of brown dwarfs unveil the rich and complex nature of an atmosphere, including non-equilibrium chemistry, non-uniform cloud distribution, and even evolving climate patterns! In my talk, I will demonstrate the power of high-precision Hubble Space Telescope (HST) spectroscopy in revealing the non-homogeneous atmosphere of a dusty brown dwarf and of a strongly irradiated brown dwarf that orbits around a white dwarf. For the coldest Y-type brown dwarf, I will share the preliminary results from the James Webb Space Telescope (JWST) NIRSpec spectroscopy that characterize a cold Y dwarf at unprecedented details, including thermal structure and exciting molecular species.