Physical Sciences and Mathematics Commons^™

The Transit Light Curve Project. X. A Christmas Transit Of Hd 17156b, Joshua N. Winn, Matthew J. Holman, Gregory W. Henry, Guillermo Torres, Debra A. Fischer, John Asher Johnson, Geoffrey W. Marcy, Avi Shporer, Tsevi Mazeh

Information Systems and Engineering Management Research Publications

Photometry is presented of the 2007 December 25 transit of HD 17156b, which has the longest orbital period and highest orbital eccentricity of all the known transiting exoplanets. New measurements of the stellar radial velocity are also presented. All the data are combined and integrated with stellar-evolutionary modeling to derive refined system parameters. The planet's mass and radius are found to be 3.212+0.069−0.082 MJup and 1.023+0.070−0.055 RJup. The corresponding stellar properties are 1.263+0.035−0.047 M☉ and 1.446+0.099−0.067 R☉. The planet is smaller by 1σ than a theoretical solar-composition gas giant with the same mass and equilibrium temperature, a possible indication of …