AOSC Seminar by Dr. Thaddeus (“Tad”) Komacek, 1/27/2022
Dr. Thaddeus Komacek
Department of Astronomy, University of Maryland
Title: Studying extreme planets as a natural fluid dynamics laboratory: atmospheric circulation and mineral cloud transport on ultra-hot Jupiters
Atmospheric characterization is the present frontier for understanding the nature of planets that orbit stars other than the Sun. To date, the bulk of the observational study of these exoplanet atmospheres has been performed on the largest and closest-in gaseous planets, colloquially termed ``hot Jupiters.’’ These hot Jupiters serve as a natural geophysical fluid dynamics laboratory to test atmospheric models in an extreme regime. Recent observations of hot Jupiters with the Spitzer and Hubble Space Telescope along with ground-based instruments have provided detailed characterization of the brightness of hot Jupiters during their rotation, enabling astronomical constraints to be placed on their atmospheric dynamics and heat transport. In this talk, I will discuss the current understanding of the atmospheric circulation of hot Jupiters as determined from interpreting astronomical observations with a combination of analytic theory and general circulation modeling. Then, I will introduce the hottest gaseous exoplanets, ``ultra-hot Jupiters,’’ as a novel class of exoplanet characterized by thermal dissociation of molecules, including their major atmospheric constituent, hydrogen. I will describe recent modeling advances to take into account the thermal dissociation of molecular to atomic hydrogen and recombination of atomic to molecular hydrogen in general circulation models of ultra-hot Jupiters, along with their impact on the global circulation. Due to the extreme temperatures on the daysides of ultra-hot Jupiters, mineral clouds made of silicates and high-temperature condensates such as aluminum and calcium-bearing oxides are expected to only condense in localized regions on the planet. I will show results from novel general circulation models that include radiatively active mineral cloud tracers in order to demonstrate how localized mixing sets the patchy cloud coverage on the nightsides of ultra-hot Jupiters. Finally, I will briefly summarize the promising future of exoplanet characterization, including the push in the coming decades toward applying techniques currently used to study hot and ultra-hot Jupiters toward smaller, cooler Earth-sized exoplanets.
Dr. Thaddeus (“Tad”) Komacek is an Assistant Professor in the Department of Astronomy at the University of Maryland, College Park. Previously, Tad held a Heising-Simons 51 Pegasi b Postdoctoral Fellowship at the University of Chicago from 2018-2021. He received his Ph.D in Planetary Sciences from the University of Arizona Lunar and Planetary Laboratory in 2018, and bachelor’s degrees in Geophysical Sciences and Physics from the University of Chicago in 2013. Dr. Komacek’s research focuses on characterizing the atmospheres of exoplanets by developing theoretical and numerical models for their global circulation and climate.
Contact: Jacob Wenegrat
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Pre-seminar refreshment: N/A
Seminar: 3:30-4:30pm, Room: ATL 2400 (only when in-person)
Meet-the-Speaker: 4:30-5:00pm, Room: ATL 3400 (only when in-person) [For AOSC Students only]