Abstract

JWST has brought on a new dawn of discovery and has completely revolutionized our understanding of exoplanet atmospheres. It has brought the opportunity to understand exoplanetary atmospheres in unprecedented detail. One of the least constrained atmospheric processes in exoplanet atmospheres is atmospheric vertical dynamics, often parametrized with the eddy diffusion parameter - Kzz. The vertical mixing process significantly impacts atmospheric chemistry and clouds, but it's currently uncertain by 6-8 orders of magnitude. I will briefly introduce atmospheric mixing and show how uncertainty in the Kzz parameter leads to uncertainty in our overall understanding of exoplanet atmospheres. I will show how the similarities between brown dwarf and exoplanet atmospheres can help us to constrain and understand the vertical mixing process better. I will present results where, using a new generation of state-of-the-art Sonora Elf Owl atmospheric models and spectroscopic data from JWST, Spitzer, and AKARI telescopes, we have constrained the vigor of atmospheric vertical mixing in the deep atmospheres of brown dwarfs. We find that the observed Kzz constraints from our work are several orders of magnitude lower than theoretical predictions. I will present what this theory-observation mismatch teaches us about the deep atmospheres of directly imaged planets and brown dwarfs. I will also discuss our recent measurement of the strength of vertical mixing and internal heat of a very young transiting sub-Neptune progenitor with JWST data.