A planet around the evolved intermediate-mass star HD 110014

• Published in: Astronomy and astrophysics (Berlin) 2009-09, Vol.504 (2), p.617-623
• Main Authors: de Medeiros, J. R., Setiawan, J., Hatzes, A. P., Pasquini, L., Girardi, L., Udry, S., Döllinger, M. P., da Silva, L.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; stars late-type; stars: evolution; stars: planetary systems; technique: radial velocities
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/200911658

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 $M_{\odot}$, 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 $835.48 \pm 6.04$ days. A Keplerian orbit, with an eccentricity $e = 0.462\pm 0.069$, yields a minimum mass $M \sin i$ = 11.09 $M_{{\rm Jup}}$. 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.