A planetary companion to the hyades giant epsilon tauri

作者：Sato Bun'ei^*; Izumiura Hideyuki; Toyota Eri; Kambe Eiji; Takeda Yoichi; Masuda Seiji; Omiya Masashi; Murata Daisuke; Itoh Yoichi; Ando Hiroyasu; Yoshida Michitoshi; Ikoma Masahiro; Kokubo Eiichiro; Ida Shigeru

来源：Astrophysical Journal, 2007, 661(1): 527-531.

DOI：10.1086/513503

• open clusters and associations : individual (Hyades)
• planetary systems
• stars : individual (epsilon Tauri)
• techniques : radial velocities

We report the detection of an extrasolar planet orbiting epsilon Tau, one of the giant stars in the Hyades open cluster. This is the first planet ever discovered in an open cluster. Precise Doppler measurements of this star from Okayama Astrophysical Observatory have revealed Keplerian velocity variations with an orbital period of 594.9 +/- 5.3 days, a semiamplitude of 95.9 +/- 1.8 m s(-1), and an eccentricity of 0.151 +/- 0.023. The minimum mass of the companion is 7.6 +/- 0.2 M-J, and the semimajor axis is 1.93 +/- 0.03 AU adopting a stellar mass of 2.7 +/- 0.1 M-circle dot. The age of 625 Myr for the cluster sets the most secure upper limit ever on the timescale of giant planet formation. The mass of 2.7 M-circle dot for the host star is robustly determined by isochrone fitting, which makes the star the heaviest among planet-harboring stars. Putting together the fact that no planets have been found around about 100 low-mass dwarfs in the cluster, the frequency of massive planets is suggested to be higher around high-mass stars than around low-mass ones.

• 出版日期2007-5-20
• 单位中国科学院国家天文台