Presentation #302.03 in the session “Atmospheric Characterization of TESS Exoplanets”.
The presence of clouds on hot giant exoplanets has been known for several years, but the usual method of their identification — transmission spectroscopy — is only sensitive to high-altitude clouds located near the planetary terminator. We will report observations of the thermal emission spectrum from the highly irradiated brown dwarf KELT-1b as a function of orbital phase, which show spectral variation indicative of changing cloud cover. These observations allow us to measure the relative cloud coverage as a function of longitude, and thereby create a detailed cloud map of KELT-1b. We will explain how the significant differences we see between this cloud map and theoretical predictions indicate that some dynamical mechanisms often omitted from GCMs need to be considered in more detail. These observations also explain anomalous results from the TESS phase curve of KELT-1b, and they confirm previous observational inferences regarding clouds from Spitzer phase curves of hot Jupiters.