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 sin i = 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 sin i = 11.09 M_Jup. 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.

Based on observations collected at the 1.52-m ESO telescope (1999 to 2002), at the 2.2-m MPG/ESO telescope (2003 to 2007), at the 3.60 ESO telescope and at the Euler swiss telescope, at the La Silla Observatory, Chile. Radial velocity measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/504/617