Retired a stars and their companions: Exoplanets orbiting three intermediate-mass subgiants

We report precision Doppler measurements of three intermediate-mass subgiants obtained at Lick and Keck Observatories. All three stars show variability in their radial velocities consistent with planet-mass companions in Keplerian orbits. We find a planet with a minimum mass MP sin i 2.5 M(J) in a 351.5 day orbit around HD 192699, a planet with a minimum mass of 2.0M(J) in a 341.1 day orbit around HD 210702, and a planet with a minimum mass of 0.61M(J) in a 297.3 day orbit around HD 175541. Mass estimates from stellar interior models indicate that all three stars were formerly A-type, main-sequence dwarfs with masses ranging from 1.65 to 1.85 M(circle dot) . These three long-period planets would not have been detectable during their stars' main-sequence phases due to the large rotational velocities and stellar jitter exhibited by early-type dwarfs. There are now nine " retired'' ( evolved) A-type stars ( M(*) > 1.6 M(circle dot)) with known planets. All nine planets orbit at distances a >= 0.78AU, which is significantly different from the semimajor axis distribution of planets around lower mass stars.