2003/12/15 by G. Hébrard, A. Lecavelier des Étangs, Hébrard, G. +9 · 25 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics (astro-ph) #Atmosphere (unit) #Exoplanet #FOS: Physical sciences #Gas giant #Giant planet #Hot Jupiter #Jupiter (rocket family) #Jupiter mass #Physics #Planet #Planetary mass #Planetary migration #Planetary system #Stars #Stellar, planetary, and galactic studies #Terrestrial planet #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0312384
published in arXiv (Cornell University) (Cornell University) · To be published in the proceedings of the XIXth IAP Colloquium "Extrasolar Planets, Today And Tomorrow", 2 pages
arxiv created 2003/12/15 · openalex publication_date 2003/12/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Among the hundred of known extrasolar planets, about 15% are closer than 0.1 AU from their parent stars. But there are extremely few detections of planets orbiting in less than 3 days. At this limit the planet HD209458b has been found to have an extended upper atmosphere of escaping hydrogen. This suggests that the so-called hot Jupiters which are close to their parent stars could evaporate. Here we estimate the evaporation rate of hydrogen from extrasolar planets in the star vicinity. With high exospheric temperatures, and owing to the tidal forces, planets evaporate through a geometrical blow-off. This may explain the absence of Jupiter mass planets below a critical distance from the stars. Below this critical distance, we infer the existence of a new class of planets made of the residual central core of former hot Jupiters, which we propose to call the ``Chthonian'' planets.