Giant planets and brown dwarfs are astrophysical objects with different formation locations – planets in disks and brown dwarfs (we think) in giant molecular clouds. These different objects transition across the very same range of Teff, with planets strongly influenced by their parent star’s heating from “above,” while brown dwarfs inexorably cool from their interior, which warms their atmospheres from “below.” This major energy difference can drive important differences between atmospheres. JWST has been revolutionizing our understanding of these cool atmospheres, and in this talk I will discuss a range of modeling work that aims to confront a variety of high signal-to-noise spectral observations, in particular for objects below Teff = 1000 K, where a number of major chemical transitions in these atmospheres occur. Our work uncovers a wide range of physical process, including vertical mixing, photochemistry, and tidal heating, which can all effect the structure and chemistry of cool atmospheres. The significant diversity in spectra stress-test our models in unique ways.

Speaker: Jonathan Fortney (University of California, Santa Cruz)

The 2024 Fall Colloquium talks are held on Wednesdays at 3:00 PM. This colloquium is hosted by STScI and will be held as an in-person and virtual event.

You may join in person at STScI’s John N. Bahcall Auditorium or virtually on STScI's Live Science Events Facebook page.

Please direct questions or comments to contact above. The 2024 Fall Colloquium Committee members are: Nestor Espinoza (STScI), Joel Green (STScI), Nick Indriolo (STScI), Elena Manjavacas (STScI), Namrata Roy (JHU), Kevin Schlaufman (JHU), Ethan Vishniac (JHU).