A planet around the evolved intermediate-mass star HD 110014

Abstract

Context. We found evidence for a sub–stellar companion around the K giant star HD 110014. This cool evolved star, with a spectral type K2III and an estimated mass between 1.9 and 2.4 M� , is slightly metal rich with [Fe/H] = 0.19 and a rotational velocity V sini = 2.0 km s −1 . Aims. To search for extrasolar planets around intermediate-mass stars and to improve our knowledge of the nature of radial velocity variations shown by G and K giant stars. Methods. Based on radial velocity analysis, we found evidence for a substellar companion with a planetary mass and long orbital period. The Radial velocity variation of HD 110014 has been monitored from 2000 until 2007 with FEROS at 1.5 m ESO and at the 2.2 m MPG/ESO, HARPS at the 3.6 m ESO and Coralie at 1.2 m Leonard Euler swiss telescopes in La Silla observatory. The radial velocities were computed by using a cross-correlation technique. Line bisector, Hipparcos photometry and chromospheric lines were analyzed to exclude other root-causes for the radial velocity variability. Results. We report the presence of an extrasolar planet around the giant star HD 110014, with an orbital period of 835.48 ± 6.04 days. A Keplerian orbit, with an eccentricity e = 0.462 ± 0.069, yields a minimum mass M sini = 11.09 MJup. The analysis of the residuals shows evidence for a second RV variability with a period of 130 days and an amplitude of ±100 ms −1 . Its nature is not completely clear, but a second planet is a possible explanation.