2005/08/01 by David Charbonneau, Joshua N. Winn, David W. Latham +9 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/497959
published as Astrophys.J. 636 (2005) 445-452 · 18 pages, 4 figures, submitted to ApJ
arxiv created 2005/08/01 · openalex publication_date 2005/12/21 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We report g , V , and r photometric time series of HD 149026 spanning predicted times of transit of the Saturn-mass planetary companion, which was recently discovered by Sato and collaborators. We present a joint analysis of our observations and the previously reported photometry and radial velocities of the central star. We refine the estimate of the transit ephemeris to T c = (2,453,527.87455 ) + (2.87598 ) N (HJD). Assuming that the star has a radius of 1.45 ± 0.10 R ☉ and a mass of 1.30 ± 0.10 M ☉ , we estimate the planet radius to be (0.726 ± 0.064) R Jup , which implies a mean density of 1.07 g cm -3 . This density is significantly greater than predicted for models that include the effects of stellar insolation and in which the planet has only a small core of solid material. Thus, we confirm that this planet likely contains a large core and that the ratio of core mass to total planet mass is more akin to that of Uranus and Neptune than to either Jupiter or Saturn.