event
Tuesday 27 Jun 2017: Cloud formation and evolution in hot Jupiter atmospheres
Stefan Lines - University of Exeter
4th Floor Interaction Area 11:15-11:45
Recent HST observations of hot Jupiter atmospheres have revealed a continuum in atmospheric
composition from cloudy to clear skies. The presence of clouds is inferred from a grey
opacity in the near-IR that mutes key absorption features in the transmission spectra. This
observational challenge inhibits the retrieval of key information including the atmospheric
chemical composition and thermal structure. Unlike the L-T Brown Dwarf sequence, this
transition does not correlate well with equilibrium temperature, suggesting that a cloud formation
scheme more comprehensive than simply considering the condensation temperature
needed for homogenous cloud growth, is required. In this talk, we follow and extend the
pioneering study of Lee et al., (2016) by performing 3D simulations of cloud nucleation,
growth, advection, evaporation and gravitational settling in the atmospheres of HD209458b
and HD189733b using the kinetic and mixed-grain cloud formation code DIHRT, coupled
to the Met Office GCM, the ’Unified Model’. We explore cloud composition, vertical structure
and particle sizes, as well as highlighting the importance of the strong atmospheric
dynamics seen in tidally locked hot Jupiters on the evolution and distribution of the cloud.
The completeness of the radiative transfer (i.e. inclusion of scattering) and the dynamics
provided by our new model, will represent the most physically complete theoretical tool for
the study of hot Jupiters.