Determination of the Orbit of the Planetary Companion to the Metal-Rich Star HD 45350

We present precise radial velocity data for the metal-rich star HD 45350 collected with the Harlan J. Smith (HJS) 2.7 m telescope and the Hobby-Eberly Telescope (HET) at McDonald Observatory. This star was noticed by us as a candidate for having a giant planetary companion in a highly eccentric orbit, but the lack of data close to periastron left the amplitude and thus the mass of the planet poorly constrained. Marcy et al. (2005) announced the presence of the planet based on their Keck HIRES data, but those authors also cautioned that the remaining uncertainties in the orbital solution might be large due to insufficient data near periastron passage. In order to close this phase gap we exploited the flexible queue-scheduled observing mode of the HET to obtain intensive coverage of the most recent periastron passage of the planet. In combination with the long-term data from the HJS 2.7 m telescope we determine a Keplerian orbital solution for this system with a period of 962 days, an eccentricity of e=0.76, and a velocity semiamplitude K of 57.4 m s^-1. The planet has a minimum mass of msini=1.82M_J+/-0.14M_J and an orbital semimajor axis of a=1.92+/-0.07 AU.

Based on observations obtained with the Harlan J. Smith Telescope and the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.