Detection of an exoplanet around the evolved K giant HD 66141

Abstract

Aims. We have been carrying out a precise radial velocity (RV) survey for K giants to search for and study the origin of the lowamplitude and long-periodic RV variations. Methods. We present high-resolution RV measurements of the K2 giant HD 66141 from December 2003 to January 2011 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO). Results. We find that the RV measurements for HD 66141 exhibit a periodic variation of 480.5 +/- 0.5 days with a semi-amplitude of 146.2 +/- 2.7 m/s. The Hipparcos photometry and bisector velocity span (BVS) do not show any obvious correlations with RV variations. We find indeed 706.4 +/- 35.0 day variations in equivalent width (EW) measurements of H_alpha line and 703.0 +/- 39.4 day variations in a space-born measurements 1.25μ flux of HD 66141 measured during COBE/DIRBE experiment. We reveal that a mean value of long-period variations is about 705 +/- 53 days and the origin is a rotation period of the star and variability that is caused by surface inhomogeneities. For the 480 day periods of RV variations an orbital motion is the most likely explanation. Assuming a stellar mass of 1.1 +/- 0.1 M_Sun? for HD 66141, we obtain a minimum mass for the planetary companion of 6.0 +/- 0.3 M_Jup with an orbital semi-major axis of 1.2 +/- 0.1 AU and an eccentricity of 0.07 +/- 0.03.

7 pages, 10 figures, 3 tables, accepted for publisation in Astronomy & Astrophysics

References in corpus (8)

• Basic physical parameters of a selected sample of evolved stars
• Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants
• Planets around evolved intermediate-mass stars. I. Two substellar companions in the open clusters NGC 2423 and NGC 4349
• Confirmation of the Planet Hypothesis for the Long-period Radial Velocity Variations of Beta Geminorum
• A Planetary Mass Companion to the K0 Giant HD 17092
• The BOES spectropolarimeter for Zeeman measurements of stellar magnetic fields
• A likely exoplanet orbiting the oscillating K-giant α Arietis
• Precise Radial Velocities of Polaris: Detection of Amplitude Growth

Cited by in corpus (5)

• Simulations of two-planet systems through all phases of stellar evolution: implications for the instability boundary and white dwarf pollution
• The Radial Velocity Variability of the K-giant Gamma Draconis: Stellar Variability Masquerading as a Planet
• Long-period variations in the radial velocity of spectroscopic binary m giant mu ursae majoris
• A Search for Exoplanets around Northern Circumpolar Stars. IV. Six Planet Candidates to the K Giants, HD 44385, HD 97619, HD 106574, HD 118904, HD 164428, and HD 202432
• Search for Exoplanets around Northern Circumpolar Stars V. Three likely planetary companions to the giant stars HD 19615, HD 150010, and HD 174205