Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458

We present evolutionary models for cool brown dwarfs and extra-solar giant planets. The models reproduce the main trends of observed methane dwarfs in near-IR color-magnitude diagrams. We also present evolutionary models for irradiated planets, coupling for the first time irradiated atmosphere profiles and inner structures. We focus on HD 209458-like systems and show that irradiation effects can substantially affect the radius of sub-jovian mass giant planets. Irradiation effects, however, cannot alone explain the large observed radius of HD 209458b. Adopting assumptions which optimise irradiation effects and taking into account the extension of the outer atmospheric layers, we still find ~20% discrepancy…

• NS
  National Science Foundation

  Awards: 0086246, 9720704
• NA
  National Aeronautics and Space Administration
• WS
  Wichita State University
• UO
  University of Georgia
• SD
  San Diego Supercomputer Center
• NE
  National Energy Research Scientific Computing Center
• MF
  Max-Planck-Institut für Astrophysik
• OO
  Office of Experimental Program to Stimulate Competitive Research