EDP Sciences
Free access
Volume 418, Number 1, April IV 2004
Page(s) L1 - L4
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20040106

A&A 418, L1-L4 (2004)
DOI: 10.1051/0004-6361:20040106


Atmospheric escape from hot Jupiters

A. Lecavelier des Etangs1, A. Vidal-Madjar1, J. C. McConnell2 and G. Hébrard1

1  Institut d'Astrophysique de Paris, CNRS, 98bis boulevard Arago, 75014 Paris, France
2  Department of Earth and Atmospheric Science, York University, North York, Ontario, Canada

(Received 10 November 2003 / Accepted 4 March 2004)

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- $\alpha$ 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.

Key words: star: individual: HD 209458 -- stars: planetary systems

Offprint request: A. Lecavelier des Etangs, lecaveli@iap.fr

SIMBAD Objects

© ESO 2004

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.