LESIA - Observatoire de Paris

Composition and distribution of clouds in exoplanets : an L/T-like transition for hot Jupiters ?

lundi 9 janvier 2017, par Vivien Parmentier (Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona)

Lundi 30 janvier 2017 à 16h00 , Lieu : Salle de conférence du bâtiment 17

Over a large range of equilibrium temperatures clouds seem to dominate the transmission spectrum of exoplanets atmospheres but no trends allowing the classification of these objects have yet emerged. Recently, Kepler observations of the light reflected by hot Jupiters show that an inhomogeneous, asymetric and time-dependent cloud coverage is present in these planets. Interesingly, the properties of these clouds depend on the equilibrium temperature of the planet. Using state-of-the-art three dimensional models of hot Jupiters atmospheres I will show why longitudinal and latitudinal assymetry in the cloud coverage is expected for these hot planets. The presence of such an inhomogeneous cloud coverage can bias the retrieved abundances from transmission and secondary eclipse spectra and even lead to erroneous molecular detections. The longitudinal cloud asymetry being a strong function of the condensation temperature of the cloud species, it is a telltale of the cloud composition. Observations and models converge towards a similar conclusion : an L/T-like transition is expected for hot Jupiters, with silicate clouds disappearing from the cooler planets and being replaced by manganese sulfide clouds.

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