Date: Wednesday 29-Nov-2023
Time: 11:30-12:30 pm
Location: PSC 1136
Speaker: Sagnick Mukherjee (UC Santa Cruz)
Title: Constraints on Atmospheric Mixing in Brown Dwarf and Exoplanet Atmospheres in the JWST Era
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 how we are trying to measure Kzz in transiting exoplanet atmospheres using the PICASO model and observations from our MANATEE JWST collaboration.
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Past CTC Lunch seminars.
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SPECIAL ACCOMMODATIONS:
Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
