A Hot Jupiter Orbiting the 1.7 M sun Subgiant HD 102956

We report the detection of a giant planet in a 6.4950 day orbit around the 1.68 M _sun subgiant HD 102956. The planet has a semimajor axis a = 0.081 AU and a minimum mass M_P sin i =0.96 M _Jup. HD 102956 is the most massive star known to harbor a hot Jupiter, and its planet is only the third known to orbit within 0.6 AU of a star more massive than 1.5 M _sun. Based on our sample of 137 subgiants with M _sstarf>1.45 M _sun, we find that 0.5%-2.3% of A-type stars harbor a close-in planet (a < 0.1 AU) with M_P sin i > 1 M _Jup, consistent with hot-Jupiter occurrence for Sun-like stars. Thus, the paucity of planets with 0.1 AU < a < 1.0 AU around intermediate-mass stars may be an exaggerated version of the "period valley" that is characteristic of planets around Sun-like stars.

Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by both NASA and the University of California.