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The orbital motion, absolute mass and high-altitude winds of exoplanet HD 209458b

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Abstract

For extrasolar planets discovered using the radial velocity method1, the spectral characterization of the host star leads to a mass estimate of the star and subsequently of the orbiting planet. If the orbital velocity of the planet could be determined, the masses of both star and planet could be calculated using Newton’s law of gravity, just as in the case of stellar double-line eclipsing binaries. Here we report high-dispersion ground-based spectroscopy of a transit of the extrasolar planet HD 209458b. We see a significant wavelength shift in absorption lines from carbon monoxide in the planet’s atmosphere, which we conclude arises from a change in the radial component of the planet’s orbital velocity. The masses of the star and planet are 1.00 ± 0.22MSun and 0.64 ± 0.09MJup respectively. A blueshift of the carbon monoxide signal of approximately 2 km s−1 with respect to the systemic velocity of the host star suggests the presence of a strong wind flowing from the irradiated dayside to the non-irradiated nightside of the planet within the 0.01–0.1 mbar atmospheric pressure range probed by these observations. The strength of the carbon monoxide signal suggests a carbon monoxide mixing ratio of (1–3) × 10−3 in this planet’s upper atmosphere.

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Figure 1: CO signal in the transmission spectrum of exoplanet HD 209458b.
Figure 2: The expected carbon monoxide signal as function of the planet orbital velocity.
Figure 3: The carbon monoxide signal integrated over the transit.

References

  1. 1

    Schneider, J. The Extrasolar Planets Encyclopaedia. 〈http://www.exoplanet.eu

  2. 2

    Käufl, H. U. et al. CRIRES: a high resolution infrared spectrograph for ESO’s VLT. Proc. SPIE 5492, 1218–1227 (2004)

    ADS  Article  Google Scholar 

  3. 3

    Arsenault, R. et al. MACAO-VLTI: an adaptive optics system for the ESO VLT interferometer. Proc. SPIE 4839, 174–185 (2003)

    ADS  Article  Google Scholar 

  4. 4

    Burrows, A., Ibgui, L. & Hubeny, I. Optical albedo theory of strongly irradiated giant planets: the case of HD 209458b. Astrophys. J. 682, 1277–1282 (2008)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Swain, M. R., Vasisht, G. & Tinetti, G. The presence of methane in the atmosphere of an extrasolar planet. Nature 452, 329–331 (2008)

    ADS  CAS  Article  Google Scholar 

  6. 6

    Madhusudhan, N. & Seager, S. A temperature and abundance retrieval method for exoplanet atmospheres. Astrophys. J. 707, 24–39 (2009)

    ADS  CAS  Article  Google Scholar 

  7. 7

    Rothman, L. S. et al. The HITRAN 2008 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Transf. 110, 533–572 (2009)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Laughlin, G., Marcy, G. W., Vogt, S. S., Fischer, D. A. & Butler, R. P. On the eccentricity of HD 209458b. Astrophys. J. 629, L121–L124 (2005)

    ADS  Article  Google Scholar 

  9. 9

    Butler, R. P. et al. Catalog of nearby exoplanets. Astrophys. J. 646, 505–522 (2006)

    ADS  CAS  Article  Google Scholar 

  10. 10

    Deming, D., Seager, S., Richardson, L. J. & Harrington, J. Infrared radiation from an extrasolar planet. Nature 434, 740–743 (2005)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Knutson, H. A. et al. Using stellar limb-darkening to refine the properties of HD 209458b. Astrophys. J. 655, 564–575 (2007)

    ADS  Article  Google Scholar 

  12. 12

    Fischer, D. A. & Valenti, J. The planet-metallicity correlation. Astrophys. J. 622, 1102–1117 (2005)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Cody, A. M. & Sasselov, D. D. HD 209458: physical parameters of the parent star and the transiting planet. Astrophys. J. 569, 451–458 (2002)

    ADS  Article  Google Scholar 

  14. 14

    Tinetti, G. et al. Water vapour in the atmosphere of a transiting extrasolar planet. Nature 448, 169–171 (2007)

    ADS  CAS  Article  Google Scholar 

  15. 15

    Grillmair, C. J. et al. Strong water absorption in the dayside emission spectrum of the planet HD189733b. Nature 456, 767–769 (2008)

    ADS  CAS  Article  Google Scholar 

  16. 16

    Swain, M. R. et al. Molecular signatures in the near-infrared dayside spectrum of HD 189733b. Astrophys. J. 690, L114–L117 (2009)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Beaulieu, J.-P. et al. Water in HD 209458b’s atmosphere from 3.6–8 microns IRAC photometric observations in primary transit. Mon. Not. R. Astron. Soc. (in the press); preprint at 〈http://arxiv.org/abs/0909.0185〉 (2009)

  18. 18

    Swain, M. R. et al. Water, methane, and carbon dioxide present in the dayside spectrum of the exoplanet HD 209458b. Astrophys. J. 704, 1616–1621 (2009)

    ADS  CAS  Article  Google Scholar 

  19. 19

    Goodman, J. Thermodynamics of atmospheric circulation on hot Jupiters. Astrophys. J. 693, 1645–1649 (2008)

    ADS  Article  Google Scholar 

  20. 20

    Showman, A. P., Cooper, C. S., Fortney, J. J. & Marley, M. S. Atmospheric circulation of hot Jupiters: three-dimensional circulation models of HD 209458b and HD 189733b with simplified forcing. Astrophys. J. 682, 559–576 (2008)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Mazeh, T. et al. The spectroscopic orbit of the planetary companion transiting HD 209458. Astrophys. J. 532, L55–L58 (2000)

    ADS  CAS  Article  Google Scholar 

Download references

Acknowledgements

We thank the ESO support staff of the Paranal Observatory for their help during the observations. This work is based on observations collected at the European Southern Observatory (383.C-0045A). S.A. acknowledges support by a Rubicon fellowship from the Netherlands Organisation for Scientific Research (NWO).

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I.A.G.S. participated in the development of the concept of this research and the analysis code, participated in the observations, the analysis and interpretation of the data and writing the manuscript. R.J.d.K. developed the planet atmosphere models and participated in the analysis and interpretation of the data and writing the manuscript. E.J.W.d.M. participated in the development of the concept of this research, and in the analysis and interpretation of the data and writing the manuscript. S.A. participated in the development of the concept of this research, and in the analysis and interpretation of the data and writing the manuscript.

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Correspondence to Ignas A. G. Snellen.

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The authors declare no competing financial interests.

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Supplementary Information

This file contains Supplementary Information comprising: Observational set-up; Data reduction and analysis; The model transmission spectra; The cross-correlation analysis; Supplementary Figures S1-S2 with legends and References. (PDF 782 kb)

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Snellen, I., de Kok, R., de Mooij, E. et al. The orbital motion, absolute mass and high-altitude winds of exoplanet HD 209458b. Nature 465, 1049–1051 (2010). https://doi.org/10.1038/nature09111

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