2004/03/16 by A. Lecavelier des Etangs, A. Vidal‐Madjar, A. Vidal-Madjar +3 · 8 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmosphere (unit) #Atmospheric escape #Atmospheric sciences #Exoplanet #Giant planet #Hot Jupiter #Meteorology #Physics #Planet #Planetary system #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20040106
published as Astron.Astrophys. 418 (2004) L1-L4 · A&A Letters, in press
arxiv created 2004/03/16 · openalex publication_date 2004/04/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The extra-solar planet HD 209458b has been found to have an extended atmosphere of escaping atomic hydrogen (Vidal-Madjar et al. 2003), suggesting that “hot Jupiters” closer to their parent stars could evaporate. Here we estimate the atmospheric escape (so called evaporation rate) from hot Jupiters and their corresponding life time against evaporation. The calculated evaporation rate of HD 209458b is in excellent agreement with the H i Lyman- α observations. We find that the tidal forces and high temperatures in the upper atmosphere must be taken into account to obtain reliable estimate of the atmospheric escape. Because of the tidal forces, we show that there is a new escape mechanism at intermediate temperatures at which the exobase reaches the Roche lobe. From an energy balance, we can estimate plausible values for the planetary exospheric temperatures, and thus obtain typical life times of planets as a function of their mass and orbital distance.