Cloudy Mornings on WASP-107b: Panchromatic limb-asymmetry shows morning-to-evening temperature, SO2, and cloud variations

Exoplanet atmospheres are not homogeneous. For example, day-to-night asymmetries in atmospheric properties are well known on hot exoplanets. With the unprecedented precision of JWST, probing morning-to-evening limb-asymmetries in transit is now possible as well. This limb-asymmetry provides a new window into the three-dimensionality of atmospheres, offering a direct probe of how temperature, composition, and cloud properties vary between a planet’s morning and evening terminators. In this talk, I will present measurements of a panchromatic limb-asymmetry signal on the puffy, warm Neptune WASP-107b using JWST/NIRCam and MIRI data from 2 - 12 microns. Our results show changes in both the atmospheric scale height and the strength of molecular absorption features. In particular, these data show clear evidence for the predicted nightside chemical production of SO2, and the creation of clouds on the nightside. I will discuss how these results provide new insights for modeling the 3D dynamics and chemistry of exoplanet atmospheres, and the prospects for future limb-asymmetry observations using JWST.