Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A transiting giant planet with a temperature between 250 K and 430 K


Of the over 400 known1 exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets2, including the first terrestrial exoplanet3,4 (CoRoT-7b), have been discovered using a space mission5 designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274 days on a low eccentricity of 0.11 ± 0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a ‘temperate’ photospheric temperature estimated to be between 250 and 430 K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models6 with an inferred interior composition consistent with that of Jupiter and Saturn.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



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

Figure 1: Light curve and model fit of the CoRoT-9b transit.
Figure 2: CoRoT-9 radial velocities.
Figure 3: Evolutionary model for a CoRoT-9b like planet.
Figure 4: The orbital parameters of CoRoT-9b among extrasolar planets.


  1. Schneider, J. The Extrasolar Planets Encyclopedia〉 (1999–2010)

    Google Scholar 

  2. Dvorak, R. et al. CoRoT’s first seven planets: An overview. In Proc. “New Technologies for Probing the Diversity of Brown Dwarfs and Exoplanets” (EDP publications, 2009) preprint at 〈〉.

    Google Scholar 

  3. Léger, A. et al. Transiting exoplanets from the CoRoT space mission. VIII. CoRoT-7b: the first super-Earth with measured radius. Astron. Astrophys. 506, 287–302 (2009)

    Article  ADS  Google Scholar 

  4. Queloz, D. et al. The CoRoT-7 planetary system: two orbiting super-Earths. Astron. Astrophys. 506, 303–319 (2009)

    Article  ADS  Google Scholar 

  5. Baglin, A. et al. CoRoT: Description of the Mission and Early Results. IAU Symp. 253, 71–81 (2009)

    ADS  Google Scholar 

  6. Guillot, T. The interiors of giant planets: models and outstanding questions. Annu. Rev. Earth Planet. Sci. 33, 493–530 (2005)

    Article  ADS  CAS  Google Scholar 

  7. Perruchot, S. et al. The SOPHIE spectrograph: design and technical key-points for high throughput and high stability. Proc. SPIE 7014, 70140J (2008)

    Article  Google Scholar 

  8. Deeg, H. J. et al. Ground-based photometry of space-based transit detections: photometric follow-up of the CoRoT mission. Astron. Astrophys. 506, 343–352 (2009)

    Article  ADS  Google Scholar 

  9. Mayor, M. et al. Setting new standards with HARPS. ESO Mess. 114, 20–24 (2003)

    ADS  Google Scholar 

  10. Israelian, G. et al. Enhanced lithium depletion in Sun-like stars with orbiting planets. Nature 462, 189–191 (2009)

    Article  ADS  CAS  Google Scholar 

  11. Ibgui, L., Burrows, A. & Spiegel, D. Tidal heating models for the radii of the inflated transiting giant planets WASP-4b, WASP-6b, WASP-12b, and TrES-4. Astrophys. J. (submitted); preprint at 〈〉 (2009)

  12. Lammer, H. et al. Determining the mass loss limit for close-in exoplanets: what can we learn from transit observations? Astron. Astrophys. 506, 399–410 (2009)

    Article  ADS  Google Scholar 

  13. Miller, N., Fortney, J. J. & Jackson, B. Inflating and deflating hot Jupiters: coupled tidal and thermal evolution of known transiting planets. Astrophys. J. 702, 1413–1427 (2009)

    Article  ADS  Google Scholar 

  14. Sudarsky, D., Burrows, A. & Pinto, P. Albedo and reflection spectra of extrasolar giant planets. Astrophys. J. 535, 885–903 (2000)

    Article  ADS  Google Scholar 

  15. Showman, A. P. & Guillot, T. Atmospheric circulation and tides of “51 Pegasus b-like” planets. Astron. Astrophys. 385, 166–180 (2002)

    Article  ADS  Google Scholar 

  16. Laughlin, G. et al. Rapid heating of the atmosphere of an extrasolar planet. Nature 457, 562–564 (2009)

    Article  ADS  CAS  Google Scholar 

  17. Exodat Information System. 〈〉.

  18. Bruntt, H. et al. Abundance analysis of targets for the COROT/MONS asteroseismology missions. II. Abundance analysis of the COROT main targets. Astron. Astrophys. 425, 683–695 (2004)

    Article  ADS  CAS  Google Scholar 

  19. Bruntt, H., De Cat, P. & Aerts, C. A spectroscopic study of southern (candidate) γ Doradus stars. II. Detailed abundance analysis and fundamental parameters. Astron. Astrophys. 478, 487–496 (2008)

    Article  ADS  Google Scholar 

  20. Siess, L. Evolution of massive AGB stars. I. Carbon burning phase. Astron. Astrophys. 448, 717–729 (2006)

    Article  ADS  CAS  Google Scholar 

  21. Sing, D. K. Stellar limb-darkening coefficients for CoRoT and Kepler. Astron. Astrophys. 510, 21–27 (2010)

    Article  ADS  Google Scholar 

  22. Mandel, K. & Agol, E. Analytic light curves for planetary transit searches. Astrophys. J. 580, L171–L175 (2002)

    Article  ADS  Google Scholar 

  23. Geem, Z. W., Kim, J. H. & Loganathan, G. V. A new heuristic optimization algorithm: Harmony Search. Simulation 76, 60–68 (2001)

    Article  Google Scholar 

  24. Deleuil, M. et al. Exo-Dat: an information system in support of the CoRoT/exoplanet science. Astron. J. 138, 649–663 (2009)

    Article  ADS  Google Scholar 

  25. Morel, P. & Lebreton, Y. CESAM: a free code for stellar evolution calculations. Astrophys. Space Sci. 316, 61–73 (2008)

    Article  ADS  Google Scholar 

  26. Guillot, T. The composition of transiting giant extrasolar planets. Phys. Scr. 130, 014023 (2008)

    Article  Google Scholar 

  27. Barbieri, M. et al. HD 17156b: a transiting planet with a 21.2 day period and an eccentric orbit. Astron. Astrophys. 476, L13–L16 (2007)

    Article  ADS  CAS  Google Scholar 

  28. Fossey, S. J., Waldmann, I. P. & Kipping, D. M. Detection of a transit by the planetary companion of HD 80606. Mon. Not. R. Astron. Soc. 396, L16–L20 (2009)

    Article  ADS  Google Scholar 

  29. Moutou, C. et al. Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80606 b. Astron. Astrophys. 498, L5–L8 (2009)

    Article  ADS  CAS  Google Scholar 

  30. Garcia-Melendo, E. & McCullough, P. R. Photometric detection of a transit of HD 80606b. Astrophys. J. 698, 558–561 (2009)

    Article  ADS  Google Scholar 

Download references


The CoRoT space mission has been developed and is operated by CNES, with the contributions of Austria, Belgium, Brazil, ESA, Germany and Spain. CoRoT data are available to the public from the CoRoT archive: The team at IAC acknowledges support by grant ESP2007-65480-C02-02 of the Spanish Ministerio de Ciencia e Innovación. The German CoRoT Team (TLS and Univ. Cologne) acknowledges DLR grants 50OW0204, 50OW0603 and 50QP07011. Observations with the HARPS spectrograph were performed under the ESO programme ID 082.C-0120, and observations with the VLT/UVES under ID 081.C-0413(C).

Author Contributions H.J.D. coordinated the analysis and its interpretation. P. Barge., S.A., J.M.A., R.A., J.C., L.C., T.M., M.O., M.P. and B. Samuel contributed to the treatment of the light curve and the detection of the transits in the CoRoT data. F.B., D.Q., C.M., G.H., M.M., C.L., F. Pepe, A.H., W.B., S.A., S.U. and F. Pont prepared, performed and analysed radial velocity observations; A. Baglin, M.A., J.S., L.J., P. Bordé. A. Léger, A. Llebaria and P.B. contributed fundamentally to the definition, design and operation of the CoRoT instrument. A.E., B.T., S.C., R.D., M.F., M.G., M. Hidas, T.L., H.R., D.R., R.S., A.S., H.J.D., R.d.H., R.A., M.R., P.K., B. Stecklum and D.C. performed ground-based photometry; Sz.C., R.A., M.B. and A. S. Bonomo worked on light curve modelling and parameter fitting. M.D., H.B., D.G., J.-C.G., E.G. and M.F. constitute the team that performed the stellar typing and related observations. T.G., M. Havel, J.S., H.L., G.W. and S.F.-M. performed the modelling of the planet and the interpretation of its characteristics. All authors discussed the results and commented on the manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to H. J. Deeg.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Table

This file contains Supplementary Table 1: Measured radial velocities of CoRoT-9. (PDF 78 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Deeg, H., Moutou, C., Erikson, A. et al. A transiting giant planet with a temperature between 250 K and 430 K. Nature 464, 384–387 (2010).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing