Transcript Barman et al.

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
• Teq ~ 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 Teff 
2) slow cooling + insulation  reduced thermal gradient ( Jupiter)
 external radiative zone + slowed gravitational contraction
 R > RJupiter
• Spectra :
- Visible = reflected (Tbolo  Teff)
- IR = thermal emission
- spectral signatures (Na, K, CO, H2O)
- 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:
- H20 solid, Fe solid
- Enstatite, forsterite, CaTiO3
• Visual (reflected) + IR (thermal emission)
• Temperature (distance the star)
Classe
1
2
3
4
5
Distance Teq
qq u.a.
< 150 K
1-2 u.a.
 250 K
1 u.a.
350-800K
Espèces dominantes
CH4, NH3
H2O
H20, CH4, Na, K
0.1 u.a.
1000 K
0.05 u.a.  1400 K
CO, Na, K, Li, Ru, H20
H20, CO , nuages
remarques
IR faible
bandes de H2O
albedo faible
absence de nuages
Silicates pas visibles
cf. après
Sudarsky et al., 2003
Gas giant spectra
Sudarsky et al., 2003
Comparison to other model atmospheres
This compares our Teff=100K, logg=3.0, model irradiated with the same flux
as a particular set of models from Hubeny, Sudarsky, Burrows 2003. The
difference between the dashed line and solid black lines is the presence
(solid) and absence (dashed) of TiO & VO- opacity.
Observational Constraints
Na I D Observation
 Monochromatic radius
Rp = 1.42 +0.1/-0.13 RJup
 opacity stronger at 
Charbonneau et al., 2002
- Weaker neutral Na concentration than expected ?
- High altitude clouds (reduces the limb size)
- departure from local thermodynamic equilibrium
Discussion about HD 209458 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 (Tint=100K)
a=0.023AU
Teq=2400K
a=0.046AU
Teq=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)
- Roche Lobe: R = 3.6 Rjup
at 8.5 R*
- If the Roche Lobe fills, 10%
attenuation of Lyman 
 H2 escape
Texosphere  Teq (Lammer, Selsis
et al.)
Vidal-Madjar et al., 2003
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.
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:
http://perso.ens-lyon.fr/france.allard
Perspectives
• Phase spectra, Global Atmospheric Circulation
• Thermal Escape, Gravitational Sedimentation,
Photochemistry
• Sub- jovien and telluric Planet Atmospheres
Conclusions