A Precise Estimate of the Radius of HD 149026b
Abstract
We present Spitzer 8 micron transit observations of the extrasolar planet system HD 149026. 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_s = 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 deg. and a planet radius of 0.755 +/- 0.040 Jupiter radii. These measurements further support models in which the planet is greatly enriched in heavy elements.
Keywords
Cite
@article{arxiv.0807.1318,
title = {A Precise Estimate of the Radius of HD 149026b},
author = {Philip Nutzman and David Charbonneau and Joshua N. Winn and Heather A. Knutson and Jonathan J. Fortney and Matthew J. Holman and Eric Agol},
journal= {arXiv preprint arXiv:0807.1318},
year = {2009}
}
Comments
To appear in the Proceedings of the 253rd IAU Symposium: "Transiting Planets", May 2008, Cambridge, MA