A hot Jupiter orbiting the 1.7 M⊙ subgiant HD 102956

Abstract

We report the detection of a giant planet in a 6.4950 day orbit around the 1.68M⊙ subgiant HD 102956. The planet has a semimajor axis a = 0.081 AU and a minimum mass MP sin i = 0.96 MJup. 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 1.5M ⊙. Based on our sample of 137 subgiants with M* > 1.45M⊙, we find that 0.5%-2.3% of A-type stars harbor a close-in planet (a < 0.1 AU) with MP sini > 1 MJup, 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. © 2010. The American Astronomical Society. All rights reserved.