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N. Iro, B. Bézard (Obs. Paris Meudon, LESIA), T. Guillot (OCA/Cassini)
Both the atmospheric circulation and evolution of hot Jupiters are strongly affected by how and where stellar energy is deposited in their atmospheres (Guillot and Showman 2002, Showman and Guillot 2002). Recently, the observation of HD209458b, transiting its star, provided a measurement of its radius which, combined with its mass, constrains for the first time evolutionary models of hot Jupiters. The radius (obtained as a function of time) depends strongly on the temperature obtained at the bottom of the ``atmosphere'' (the layer which is penetrated by the stellar flux). We present here a radiative equilibrium model of HD209458b. Heating ang cooling derive respectively from the absorption of the stellar flux and the thermal emision of the planet. Radiative transfer calculations incorporate collision-induced opacity from H2-He, Rayleigh scaterring from H2 and He, bound-free absorption by H-, free-free absorption by H2-, molecular bands from H2O, CH4 and CO, and resonance lines from alkali metals. Abundances profiles are calculated assuming solar elemental abundances and thermochemical equilibrium. Preliminary results will be presented and implications on dynamical and evolutionary models will be discussed.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.