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arXiv · 0709.0645

A Substellar Companion to the Intermediate-Mass Giant 11 Com

Y. J. Liu·Bun'ei Sato·G. Zhao·Kunio Noguchi·H. Wang·Eiji Kambe·Hiroyasu Ando·Hideyuki Izumiura·Y. Q. Chen·Norio Okada·Eri Toyota·Masashi Omiya·Seiji Masuda·Yoichi Takeda·Daisuke Murata·Yoichi Itoh·Michitoshi Yoshida·Eiichiro Kokubo·Shigeru Ida
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Abstract

We report the detection of a substellar companion orbiting the intermediate-mass giant star 11 Com (G8 III). Precise Doppler measurements of the star from Xinglong station and Okayama Astrophysical Observatory (OAO) revealed Keplerian velocity variations with an orbital period of 326.03 +/- 0.32 days, a semiamplitude of 302.8 +/- 2.6 m/s, and an eccentricity of 0.231 +/- 0.005. Adopting a stellar mass of 2.7 +/- 0.3 M_solar, the minimum mass of the companion is 19.4 +/- 1.5 M_Jup, well above the deuterium burning limit, and the semimajor axis is 1.29 +/- 0.05 AU. This is the first result from the joint planet search program between China and Japan aiming at revealing statistics of substellar companions around intermediate-mass giants. 11 Com b emerged from 300 targets of the planet search program at OAO. The current detection rate of a brown dwarf candidate seems to be comparable to that around solar-type stars within orbital separations of $\sim$3 AU.

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Y. J. Liu, Bun'ei Sato, G. Zhao, Kunio Noguchi, H. Wang, Eiji Kambe, Hiroyasu Ando, Hideyuki Izumiura, Y. Q. Chen, Norio Okada, Eri Toyota, Masashi Omiya, Seiji Masuda, Yoichi Takeda, Daisuke Murata, Yoichi Itoh, Michitoshi Yoshida, Eiichiro Kokubo, Shigeru Ida. 2007-09-05. A Substellar Companion to the Intermediate-Mass Giant 11 Com. https://doi.org/10.1086/523297

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