Nutzman, PhilipCharbonneau, DavidWinn, Joshua N.Knutson, Heather A.Fortney, Jonathan J.Holman, Matthew J.Agol, Eric2019-09-242009Nutzman, Philip, David Charbonneau, Joshua N. Winn, Heather A. Knutson, Jonathan J. Fortney, Matthew J. Holman, and Eric Agol. 2009. “A PRECISE ESTIMATE OF THE RADIUS OF THE EXOPLANET HD 149026b FROM SPITZER PHOTOMETRY.” The Astrophysical Journal 692 (1): 229–35. https://doi.org/10.1088/0004-637x/692/1/229.0004-637X1538-4357http://nrs.harvard.edu/urn-3:HUL.InstRepos:41397482We present Spitzer 8 mu m 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 R(p)/R(star) = 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 degrees.4(-0 degrees.8)(+0 degrees.9) and a planet radius of R(p) = 0.755 +/- 0.040 R(J). These measurements further support models in which the planet is greatly enriched in heavy elements.en-USJournal Article2019-09-2410.1088/0004-637X/692/1/229