Physical Sciences and Mathematics Commons^™

A Determination Of The Spin-Orbit Alignment Of The Anomalously Dense Planet Orbiting Hd 149026, Aaron S. Wolf, Gregory Laughlin, Gregory W. Henry, Debra A. Fischer, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt

Information Systems and Engineering Management Research Publications

We report 35 radial velocity measurements of HD 149026 taken with the Keck Telescope. Of these measurements, 15 were made during the transit of the companion planet HD 149026b, which occurred on 2005 June 25. These velocities provide a high-cadence observation of the Rossiter-McLaughlin effect, the shifting of photospheric line profiles that occurs when a planet occults a portion of the rotating stellar surface. We combine these radial velocities with previously published radial velocity and photometric data sets and derive a composite best-fit model for the star-planet system. This model confirms and improves previously published orbital parameters, including the remarkably …