2018MNRAS.481.5315S

We present a 3D fully self-consistent multifluid hydrodynamic aeronomy model to study the structure of a hydrogen-dominated expanding upper atmosphere around the hot Jupiter HD 209458b and the warm Neptune GJ 436b. In comparison to previous studies with 1D and 2D models, this work finds such 3D features as zonal flows in upper atmosphere reaching up to 1 km s^–1, the tilting of the planetary outflow by Coriolis force by up to 45 degrees and its compression around equatorial plane by tidal forces. We also investigated in detail the influence of helium (He) on the structure of the thermosphere. It is found that by decrease of the barometric scale height, the He presence in the atmosphere strongly affects the H₂ dissociation front and the temperature maximum.