A precise estimate of the radius of the exoplanet HD 149026b from spitzer photometry

Philip Nutzman, David Charbonneau, Joshua N. Winn, Heather A. Knutson, Jonathan J. Fortney, Matthew J. Holman, Eric Agol

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Abstract

We present Spitzer 8 μm transit observations of the extrasolar planet HD 149026b. At this wavelength, transit light curves are weakly affected by stellar limb darkening, allowing for a simpler and more accurate determination of planetary parameters. We measure a planet-star radius ratio of Rp /R* = 0.05158 ± 0.00077, and in combination with ground-based data and independent constraints on the stellar mass and radius, we derive an orbital inclination i = 85°.4+0°.9-0°.8 of and a planet radius of Rp = 0.755 ± 0.040 RJ. These measurements further support models in which the planet is greatly enriched in heavy elements.

Original languageEnglish (US)
Pages (from-to)229-235
Number of pages7
JournalAstrophysical Journal
Volume692
Issue number1
DOIs
StatePublished - Feb 10 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • planetary systems
  • techniques: photometric

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    Nutzman, P., Charbonneau, D., Winn, J. N., Knutson, H. A., Fortney, J. J., Holman, M. J., & Agol, E. (2009). A precise estimate of the radius of the exoplanet HD 149026b from spitzer photometry. Astrophysical Journal, 692(1), 229-235. https://doi.org/10.1088/0004-637X/692/1/229