Tom Evans-Soma

An ultrahot Jupiter phase curve measured with JWST

Ultrahot Jupiters provide laboratories for studying planetary atmospheres under extreme conditions. I will present a phase curve measurement made for the archetypal ultrahot Jupiter WASP-121b using JWST. The data provide thermal emission spectra for the planet’s dayside and nightside hemispheres, across a wavelength range of 3-5 micron. We identify multiple gas species, offering new insights into the atmospheric chemistry, thermal structure, and dynamics of WASP-121 b. Our results provide strong evidence for vigorous vertical mixing on the planet’s nightside hemisphere driving the relative abundances of key molecules. Additionally, the elemental abundances and abundance ratios that we measure provide new insights into the roles of pebbles and planetesimals in the formation of WASP-121 b.