학술논문
A wide star-black-hole binary system from radial-velocity measurements
Document Type
Working Paper
Author
Liu, Jifeng; Zhang, Haotong; Howard, Andrew W.; Bai, Zhongrui; Lu, Youjun; Soria, Roberto; Justham, Stephen; Li, Xiangdong; Zheng, Zheng; Wang, Tinggui; Belczynski, Krzysztof; Casares, Jorge; Zhang, Wei; Yuan, Hailong; Dong, Yiqiao; Lei, Yajuan; Isaacson, Howard; Wang, Song; Bai, Yu; Shao, Yong; Gao, Qing; Wang, Yilun; Niu, Zexi; Cui, Kaiming; Zheng, Chuanjie; Mu, Xiaoyong; Zhang, Lan; Wang, Wei; Heger, Alexander; Qi, Zhaoxiang; Liao, Shilong; Lattanzi, Mario; Gu, Wei-Min; Wang, Junfeng; Wu, Jianfeng; Shao, Lijing; Shen, Rongfeng; Wang, Xiaofeng; Bregman, Joel; Di Stefano, Rosanne; Liu, Qingzhong; Han, Zhanwen; Zhang, Tianmeng; Wang, Huijuan; Ren, Juanjuan; Zhang, Junbo; Zhang, Jujia; Wang, Xiaoli; Cabrera-Lavers, Antonio; Corradi, Romano; Rebolo, Rafael; Zhao, Yongheng; Zhao, Gang; Chu, Yaoquan; Cui, Xiangqun
Source
Nature, 575, 618-621 (2019)
Subject
Language
Abstract
All stellar mass black holes have hitherto been identified by X-rays emitted by gas that is accreting onto the black hole from a companion star. These systems are all binaries with black holes below 30 M$_{\odot}$$^{1-4}$. Theory predicts, however, that X-ray emitting systems form a minority of the total population of star-black hole binaries$^{5,6}$. When the black hole is not accreting gas, it can be found through radial velocity measurements of the motion of the companion star. Here we report radial velocity measurements of a Galactic star, LB-1, which is a B-type star, taken over two years. We find that the motion of the B-star and an accompanying H$\alpha$ emission line require the presence of a dark companion with a mass of $68^{+11}_{-13}$ M$_{\odot}$, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. The gravitational wave experiments have detected similarly massive black holes$^{7,8}$, but forming such massive ones in a high-metallicity environment would be extremely challenging to current stellar evolution theories$^{9-11}$.
Comment: Published in Nature on Nov 28, 2019
Comment: Published in Nature on Nov 28, 2019