Shedding light on the atmospheres of hot Jupiters: maps, clouds, and a SYMPHONY

In this dissertation talk, I will discuss my work looking for trends in dayside and nightside temperatures on hot Jupiters, using secondary eclipses and phase curves. I'll compare and contrast the Spitzer phase curves of WASP-43b and Qatar-1b, two planets that receive the same amount of irradiation from their host stars, yet unexpectedly have very different bright spot offsets: WASP-43b has a significant eastward shifted bright spot, whereas we found that the bright spot of Qatar-1b is consistent with no such shift. The discrepancy in circulation patterns points to the importance of secondary parameters like rotation rate and surface gravity, and the presence or absence of clouds, in determining atmospheric conditions on hot Jupiters.

However, we did find that the nightsides of the two planets had the same temperature, after correcting for the unphysical maps of WASP-43b. In fact, using a larger suite of phase curves and their corresponding longitudinal brightness maps, we showed that all hot Jupiters have nightside temperatures around 1000 K, which we attributed to a universal nightside cloud species, the most likely culprit being silicate clouds, according to microphysical cloud models.

Lastly, I'll discuss my recent work applying Bayesian hierarchical models to simultaneously fit multiple Spitzer secondary eclipses of hot Jupiters. By sharing information about the Spitzer IRAC detector sensitivity and eclipse depths for multiple planets, I'll show that we are able to more precisely constrain the individual eclipse depths than fitting them individually. This type of analysis is useful for all statistical surveys of exoplanets, including those that will be undertaken with James Webb and ARIEL.