Discovery of a planet around the K giant star 4 Ursae Majoris
Discovery of a planet around the K giant star 4 Ursae Majoris
复制标题
DOI：
10.1051/0004-6361:20066987
复制
发表时间：
2007-03
影响因子：
6.5
通讯作者：
M. Doellinger;A. Hatzes;L. Pasquini;E. Guenther;M. Hartmann;L. Girardi;M. Esposito
中科院分区：
文献类型：
--
作者：
M. Doellinger;A. Hatzes;L. Pasquini;E. Guenther;M. Hartmann;L. Girardi;M. Esposito
在过去的3年里，我们一直在监测62 K巨星的样本，使用精确的恒星径向速度测量，高精度在图林根Landessternwarte陶滕堡。我们寻找巨星的亚恒星同伴，并试图了解K巨星所表现出的不同径向速度变化的性质。本文介绍了K1 III巨星星星4 UMa（HD 73108）的恒星径向速度的精确测量结果。这些都是使用2米阿尔弗雷德詹士望远镜的Coude阶梯光谱仪获得的。径向速度测量的波长参考由碘吸收池提供。我们的测量结果表明，4UMa的径向速度具有269.3天的周期变化，半振幅K = 216.8m·s-1。对于径向速度的变化，最合理的解释是一个偏心率为e = 0.43 ± 0.02的开普勒轨道。轨道产生一个质量函数，$f（m）=（2.05 \pm 0.24）\times 10^{- 7}~M_{\odot}$。从我们的高分辨率光谱，我们计算出的金属丰度为-0.25 ± 0.05，并推导出恒星质量为1.23 $M_{\odot} \pm 0.15$的主机星星。K巨星星星4 UMa拥有一个亚恒星伴星，其最小质量为$M\sin i = 7.1 \pm 1.6 ~M_{\rm Jupiter}$.
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 Thuringer 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 = 216.8 m s -1 . 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, $f(m) = (2.05 \pm 0.24) \times 10^{- 7}~M_{\odot}$. From our high resolution spectra we calculate a metallicity of -0.25 ± 0.05 and derive a stellar mass of 1.23 $M_{\odot} \pm 0.15$ for the host star. The K giant star 4 UMa hosts a substellar companion with minimum mass $M\sin i = 7.1 \pm 1.6 ~M_{\rm Jupiter}$.