A double planetary system around the evolved intermediate-mass star HD 4732

Abstract

We report the detection of a double planetary system orbiting around the evolved intermediate-mass star HD 4732 from precise Doppler measurements at Okayama Astrophysical Observatory and Australian Astronomical Observatory. The star is a K0 subgiant with a mass of 1.7 M⊙ and solar metallicity. The planetary system is composed of two giant planets with minimum mass of msin i = 2.4 M⊙J, orbital period of 360.2 days and 2732 days, and eccentricity of 0.13 and 0.23, respectively. Based on dynamical stability analysis for the system, we set the upper limit on the mass of the planets to be about 28 M⊙J (i > 5°) in the case of coplanar prograde configuration. © 2013. The American Astronomical Society. All rights reserved.