500K planet at 1.0, 0.5, 0.3 AU around a G2V Barman et al. (ApJ 556, 885, 2001)

Contrast Hot Jupiter vs planet at 5 AU

Hot Jupiter contrast to a G2 and M5 Day side (substellar point)

Pegasides T eq ~ 1250 K (Guillot et al. 1996) - Jeans Evaporation without danger for the planet’s survival - No mass transfer (atm < lobe de Roche) Rotation / revolution synch. : zonal winds > 1 km/s (Showman et Guillot 2002)  energy redistribution Entire convective planet : evolution in 2 phases 1) rapid contraction  T eff  2) slow cooling + insulation  reduced thermal gradient (  Jupiter)  external radiative zone + slowed gravitational contraction  R > R Jupiter Spectra : - Visible = reflected (T bolo  T eff ) - IR = thermal emission - spectral signatures (Na, K, CO, H 2 O) - role of clouds (ex. silicates) (Baraffe et al. 2003)

Atmospheres and spectra of giant exoplanets Spectra determined by the chemical composition of the external atmosphere BUT  stars (hot) condensed species that contribute to the opacity: - H 2 0 solid, Fe solid - Enstatite, forsterite, CaTiO 3 Temperature (distance the star) Visual (reflected) + IR (thermal emission) ClasseDistance TeqEspèces dominantesremarques 1qq u.a. < 150 K CH 4, NH 3 IR faible 21-2 u.a.  250 KH 2 Obandes de H 2 O 31 u.a K H 2 0, CH 4, Na, Kalbedo faible absence de nuages 40.1 u.a KCO, Na, K, Li, Ru, H 2 0Silicates pas visibles u.a.  1400 KH 2 0, CO, nuagescf. après Sudarsky et al., 2003

Gas giant spectra Sudarsky et al., 2003

This compares our T eff =100K, logg=3.0, model irradiated with the same flux as a particular set of models from Hubeny, Sudarsky, Burrows The difference between the dashed line and solid black lines is the presence (solid) and absence (dashed) of TiO & VO- opacity. Comparison to other model atmospheres

Observational Constraints Na I D Observation  Monochromatic radius Rp = /-0.13 R Jup  opacity stronger at Charbonneau et al., Weaker neutral Na concentration than expected ? - High altitude clouds (reduces the limb size) - departure from local thermodynamic equilibrium Discussion about HD b’s radius: Cf. Allard Darwin Conf. 2003

Na I D et HD209458b Barman et al. (ApJ 569, L51, 2002) Left: Monochromatic radius of HD209458b, based upon the Phoenix model atmospheres with Na in LTE (in black) and non-LTE. Right: Transit depth at wavelengths centered around the Na I D doublet, relative to the transit depth in adjacent bands, based upon the models on the left. The points are observations by Charbonneau et al. (2002).

Evolutionary Models for cool Brown Dwarfs and Extrasolar Giant Planets Baraffe et al. (A&A 402, 701, 2003)

Evolutionary Models for cool Brown Dwarfs and Extrasolar Giant Planets Baraffe et al. (A&A 402, 701, 2003)

Evolutionary Models for cool Brown Dwarfs and Extrasolar Giant Planets Baraffe et al. (A&A 402, 701, 2003)

Emergent and reflected spectra (T int =100K) a=0.023AU T eq =2400K a=0.046AU T eq =1700K Compares the SEDs for HD209458b and OGLE-TR56b. Also shows the pure reflected contributions for both. TR56b is closer and hotter to the parent star and, therefore, a larger fraction of the optical spectrum is due entirely to thermal reradiation of absorbed stellar flux. This is not the case for HD.

Lyman  observation -15% attenuation of Lyman  during the transit (1.5% of the surface) Vidal-Madjar et al., Roche Lobe: R = 3.6 R jup at 8.5 R* - If the Roche Lobe fills, 10% attenuation of Lyman  H 2 escape  H 2 escape T exosphere  T eq (Lammer, Selsis et al.)

Phase Temperature-Pressure (T-P) profile of HD209458b’s atmosphere for several concentric regions (lines of constant incident flux) around the substellar point. The upper curve corresponds to the substellar point. The dotted curves correspond to regions intermédiate to the substellar point and the terminator. The lowermost curve corresponds to the non-light hemisphere.

Perspectives Phase spectra, Global Atmospheric Circulation Thermal Escape, Gravitational Sedimentation, Photochemistry Sub- jovien and telluric Planet Atmospheres Model atmospheres, thermal profiles, spectra and synthetic photometry of Brown Dwarfs and Extrasolar Giant Planets (with and without stellar irradiation) are available for all stages of evolution:

Conclusions