Thermosphere and exosphere of Hot-Jupiters

Abstract

Here we describe the observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the "Hot-Jupiters". In particular, observations and theoretical modeling of Hot-Jupiter evaporation are described. The observations allowed the discovery that the planet orbiting HD209458 has an extended atmosphere of escaping hydrogen and showed the presence of oxygen and carbon at very high altitude. These observations give unique constraints on the escape rate and mechanism in the atmosphere of these planets. The most recent Lyman-alpha HST observations of HD189733b allows for the first time to compare the evaporation from two different planets in different environments. Models to quantify the escape rate from the measured occultation depths, and an energy diagram to describe the evaporation state of Hot-Jupiters are presented. Using this diagram, it is shown that few already known planets could be remnants of formerly giant planets.

Invited review at IAU Symposium 253 "Transiting planets". Pont F., Queloz D., Sasselov., Torres M., and Holman M., Eds

References in corpus (5)

• Detection of oxygen and carbon in the hydrodynamically escaping atmosphere of the extrasolar planet HD209458b
• A New Family of Planets ? "Ocean Planets"
• Volatile-Rich Earth-Mass Planets in the Habitable Zone
• Exoplanet HD 209458b : Evaporation strengthened
• A Spitzer Search for Water in the Transiting Exoplanet HD189733b