An extended upper atmosphere around the extrasolar planet HD209458b (original) (raw)

Nature volume 422, pages 143–146 (2003)Cite this article

Abstract

The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed1,2. Together with radial velocity measurements3, this has led to a determination of the planet's radius and mass, confirming it to be a gas giant. But despite numerous searches for an atmospheric signature4,5,6, only the dense lower atmosphere of HD209458b has been observed, through the detection of neutral sodium absorption7. Here we report the detection of atomic hydrogen absorption in the stellar Lyman α line during three transits of HD209458b. An absorption of 15 ± 4% (1_σ_) is observed. Comparison with models shows that this absorption should take place beyond the Roche limit and therefore can be understood in terms of escaping hydrogen atoms.

This is a preview of subscription content, access via your institution

Access options

Subscribe to this journal

Receive 51 print issues and online access

$199.00 per year

only $3.90 per issue

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Additional access options:

Similar content being viewed by others

References

  1. Henry, G. W., Marcy, G. W., Butler, R. P. & Vogt, S. S. A transiting “51 Peg-like” planet. Astrophys. J. 529, L41–L44 (2000)
    Article ADS CAS Google Scholar
  2. Charbonneau, D., Brown, T. M., Latham, D. W. & Mayor, M. Detection of planetary transits across a Sun-like star. Astrophys. J. 529, L45–L48 (2000)
    Article ADS CAS Google Scholar
  3. Mazeh, T. et al. The spectroscopic orbit of the planetary companion transiting HD 209458. Astrophys. J. 532, L55–L58 (2000)
    Article ADS CAS Google Scholar
  4. Bundy, K. A. & Marcy, G. W. A search for transit effects in spectra of 51 Pegasi and HD 209458. Proc. Astron. Soc. Pacif. 112, 1421–1425 (2000)
    Article ADS Google Scholar
  5. Rauer, H., Bockelée-Morvan, D., Coustenis, A., Guillot, T. & Schneider, J. Search for an exosphere around 51 Pegasi B with ISO. Astron. Astrophys. 355, 573–580 (2000)
    ADS Google Scholar
  6. Moutou, C. et al. Search for spectroscopical signatures of transiting HD 209458b's exosphere. Astron. Astrophys. 371, 260–266 (2001)
    Article ADS Google Scholar
  7. Charbonneau, D., Brown, T. M., Noyes, R. W. & Gilliland, R. L. Detection of an extrasolar planet atmosphere. Astrophys. J. 568, 377–384 (2002)
    Article ADS CAS Google Scholar
  8. Vidal-Madjar, A. Evolution of the solar lyman alpha flux during four consecutive years. Sol. Phys. 40, 69–86 (1975)
    Article ADS Google Scholar
  9. Lemaire, P. et al. in Proc. Symp. SOHO 11, From Solar Min to Max: Half a Solar Cycle with SOHO (ed. Wilson, A.) 219–222 (ESA SP-508, ESA Publications Division, Noordwijk, 2002)
    Google Scholar
  10. Prinz, D. K. The spatial distribution of Lyman alpha on the Sun. Astrophys. J. 187, 369–375 (1974)
    Article ADS CAS Google Scholar
  11. Paczynski, B. Evolutionary processes in close binary systems. Annu. Rev. Astron. Astrophys. 9, 183–208 (1971)
    Article ADS CAS Google Scholar
  12. Cumming, A., Marcy, G. W., Butler, R. P. & Vogt, S. S. The statistics of extrasolar planets: Results from the Keck survey. Preprint astro-ph/0209199 available at 〈http://xxx.lanl.gov〉 (2002).
  13. Konacki, M., Torres, G., Jha, S. & Sasselov, D. D. An extrasolar planet that transits the disk of its parent star. Nature 421, 507–509 (2003)
    Article ADS CAS Google Scholar

Download references

Acknowledgements

This work is based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc. We thank M. Lemoine, L. Ben Jaffel, C. Emerich, P. D. Feldman and J. McConnell for comments, J. Herbert and W. Landsman for conversations on STIS data reduction, and J. Valenti for help in preparing the observations.

Author information

Authors and Affiliations

  1. Institut d'Astrophysique de Paris, CNRS/UPMC, 98bis boulevard Arago, F-75014, Paris, France
    A. Vidal-Madjar, A. Lecavelier des Etangs, J.-M. Désert, R. Ferlet & G. Hébrard
  2. Lunar and Planetary Laboratory, University of Arizona, 1040 E. 4th St., Rm 901, Arizona, Tucson, 85721-0077, USA
    G. E. Ballester
  3. Observatoire de Genève, CH-1290, Sauverny, Switzerland
    M. Mayor

Authors

  1. A. Vidal-Madjar
    You can also search for this author inPubMed Google Scholar
  2. A. Lecavelier des Etangs
    You can also search for this author inPubMed Google Scholar
  3. J.-M. Désert
    You can also search for this author inPubMed Google Scholar
  4. G. E. Ballester
    You can also search for this author inPubMed Google Scholar
  5. R. Ferlet
    You can also search for this author inPubMed Google Scholar
  6. G. Hébrard
    You can also search for this author inPubMed Google Scholar
  7. M. Mayor
    You can also search for this author inPubMed Google Scholar

Corresponding author

Correspondence toA. Vidal-Madjar.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

About this article

Cite this article

Vidal-Madjar, A., des Etangs, A., Désert, JM. et al. An extended upper atmosphere around the extrasolar planet HD209458b.Nature 422, 143–146 (2003). https://doi.org/10.1038/nature01448

Download citation

This article is cited by

Associated content