2007A&A...472..649D -
Astronomy and Astrophysics, volume 472, 649-652 (2007/9-3)
Discovery of a planet around the K giant star 4 Ursae Majoris.
DOELLINGER M.P., HATZES A.P., PASQUINI L., GUENTHER E.W., HARTMANN M., GIRARDI L. and ESPOSITO M.
Abstract (from CDS):
For the past 3 years we have been monitoring a sample of 62 K giant stars using precise stellar radial velocity measurements with high accuracy taken at the Thueringer Landessternwarte Tautenburg. We search for sub-stellar companions to giant stars and try to understand the nature of the diverse radial velocity variations exhibited by K giant stars. We present precise stellar radial velocity measurements of the K1III giant star 4 UMa (HD 73108). These were obtained using the coude echelle spectrograph of 2-m Alfred Jensch Telescope. The wavelength reference for the radial velocity measurements was provided by an iodine absorption cell. Our measurements reveal that the radial velocity of 4 UMa exhibits a periodic variation of 269.3 days with a semiamplitude K=216.8m/s. A Keplerian orbit with an eccentricity, e=0.43±0.02 is the most reasonable explanation for the radial velocity variations. The orbit yields a mass function, f(m)=(2.05±0.24)x10–7M☉. From our high resolution spectra we calculate a metallicity of -0.25±0.05 and derive a stellar mass of 1.23M☉±0.15 for the host star. The K giant star 4 UMa hosts a substellar companion with minimum mass Msini=7.1±1.6MJupiter.
Abstract Copyright:
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Journal keyword(s):
star: general - stars: variables - stars: individual: 4 UMa - techniques: radial velocities - stars: late-type - stars: planetary systems
Simbad objects:
11
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