A precise estimate of the radius of HD 149026b

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

Research output: Contribution to journalArticlepeer-review


We present Spitzer 8 μm transit observations of the extrasolar planet system 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 of i = 85°.4 +0°.9-0°.8 and a planet radius of 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)466-469
Number of pages4
JournalProceedings of the International Astronomical Union
Issue numberS253
StatePublished - May 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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