Sulfur-bearing molecules have provided some of the biggest surprises from recent spectra of gas-giant exoplanets, providing insight into atmospheric metallicity, disequilibrium chemistry, and planet formation. I will share how this unexpected our exciting new results regarding detailed photochemical modeling of a new atmosphere grid, ranging from 0.3-1000x solar metallicity, 250-2000 K, and across a range of internal temperature, XUV irradiation, vertical diffusion, and elemental ratios. Our models reveal a ‘sulfur shoreline’ for SO2 that determines the key, observable sulfur-bearing species in the atmospheres of giant exoplanets. For example, we find that expected SO2 abundances depend strongly on metallicity, C/O, and overall temperature; depend somewhat on XUV irradiation; depend weakly on Kzz (except for Teq ≲ 600 K); and are essentially independent of internal temperature. We also reveal the dominant sulfur-bearing species across this wide range parameter space. I will also discuss the implications of recent measurements of Sulfur-bearing molecules beyond SO2, including H2S and CS2. These results have important implications for interpreting the growing trove of sulfur detections (and non-detections!) from JWST of directly-imaged and transiting planets, and for preparing for ESA's large-scale ARIEL survey.
Speaker: Ian Crossfield, The University of Kansas
Host: Jason Wang
CIERA Astrophysics
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