A wide star–black-hole binary system from radial-velocity measurements

Jifeng Liu, Haotong Zhang, Andrew W. Howard, Zhongrui Bai, Youjun Lu, Roberto Soria, Stephen Justham, Xiangdong Li, Zheng Zheng, Tinggui Wang, Krzysztof Belczynski, Jorge Casares, Wei Zhang, Hailong Yuan, Yiqiao Dong, Yajuan Lei, Howard Isaacson, Song Wang, Yu Bai, Yong ShaoQing Gao, Yilun Wang, Zexi Niu, Kaiming Cui, Chuanjie Zheng, Xiaoyong Mu, Lan Zhang, Wei Wang, Alexander Heger, Zhaoxiang Qi, Shilong Liao, Mario Lattanzi, Wei Min Gu, Junfeng Wang, Jianfeng Wu, Lijing Shao, Rongfeng Shen, Xiaofeng Wang, Joel Bregman, Rosanne Di Stefano, Qingzhong Liu, Zhanwen Han, Tianmeng Zhang, Huijuan Wang, Juanjuan Ren, Junbo Zhang, Jujia Zhang, Xiaoli Wang, Antonio Cabrera-Lavers, Romano Corradi, Rafael Rebolo, Yongheng Zhao, Gang Zhao, Yaoquan Chu, Xiangqun Cui

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7 Citations (Scopus)

Abstract

All stellar-mass black holes have hitherto been identified by X-rays emitted from gas that is accreting onto the black hole from a companion star. These systems are all binaries with a black-hole mass that is less than 30 times that of the Sun1–4. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star–black-hole binaries5,6. 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 taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Hα emission line require the presence of a dark companion with a mass of 68−13+11 solar masses, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. Gravitational-wave experiments have detected black holes of similar mass, but the formation of such massive ones in a high-metallicity environment would be extremely challenging within current stellar evolution theories.

Original languageEnglish
Pages (from-to)618-621
Number of pages4
JournalNature
Volume575
Issue number7784
DOIs
Publication statusPublished - 28 Nov 2019

Cite this

Liu, J., Zhang, H., Howard, A. W., Bai, Z., Lu, Y., Soria, R., Justham, S., Li, X., Zheng, Z., Wang, T., Belczynski, K., Casares, J., Zhang, W., Yuan, H., Dong, Y., Lei, Y., Isaacson, H., Wang, S., Bai, Y., ... Cui, X. (2019). A wide star–black-hole binary system from radial-velocity measurements. Nature, 575(7784), 618-621. https://doi.org/10.1038/s41586-019-1766-2