A wide star-black-hole binary system from radial-velocity measurements
- Creators
- Liu, Jifeng
-
Howard, Andrew W.
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 Sun. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star–black-hole binaries. 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^(+11)_(−13) 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.
Additional Information
© 2019 Springer Nature Limited. Received 01 March 2019; Accepted 28 August 2019; Published 27 November 2019. We thank D. Wang, J. Miller, E. Cackett, R. Narayan, H. Chen, B. Zhang, C. Motch, M. Bessel, G. Da Costa, A. Bogomazov, S. Wang and many others for helpful discussions. This work was supported by the National Science Foundation of China (NSFC) under grant numbers 11988101/11425313 (J.L.), 11773015/11333004/U1838201 (X.L.), 11603010 (Y.S.), 11690024 (Y. Lei), U1531118 (W.Z.), 11603035 (S.W.), 11733009 (Q.L.) and 11325313/11633002 (X.W.). It was also supported by the National Key Research and Development Program of China (NKRDPC) under grant numbers 2019YFA0405504 and 2016YFA0400804 (J.L.), 2016YFA0400803 (X.L.) and 2016YFA0400704 (Y. Lu). J.C. acknowledges support by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) under grant AYA2017-83216-P. K.B. acknowledges support from the Polish National Science Center (NCN) grants OPUS (2015/19/B/ST9/01099) and Maestro (2018/30/A/ST9/00050). This work was only made possible with LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope), a National Major Scientific Project built by the Chinese Academy of Sciences. Funding for the project was provided by the National Development and Reform Commission. LAMOST is operated and managed by the National Astronomical Observatories, Chinese Academy of Sciences. This work is partly based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma. Part of the data was obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The scientific results reported in this article are based in part on observations made by the Chandra X-ray Observatory (ObsID 20928). This research has made use of software provided by the Chandra X-ray Center (CXC) in the application packages CIAO. Data availability: The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request. Author Contributions: J.L. and H.Z. are equally responsible for supervising the discovery and follow-up observations. H.Z. and Z.H. proposed the LAMOST monitoring campaign, and H.Z.'s group reduced the LAMOST data with meticulous efforts. J.L. proposed the GTC/Keck/Chandra observations, and his and H.Z.'s groups carried out subsequent data reduction and analysis. J.L. wrote the manuscript with help mainly from H.Z., Y. Lu, R.S., S.W., X.L., Y.S., T.W., Y.B., Z.B., W.Z., Q.G., Y.W., Z.Z., K.B. and J.C. W.W., A.H., W.M.G., J. Wang, J. Wu, L.S., R.S., X.W., J.B., R.D.S. and Q.L. also contributed to the physical interpretation and discussion. H.Y., Y.D., Y. Lei, Z.N., K.C., C.Z., X.M., L.Z., T.Z., H.W., J.R., Junbo Zhang, Jujia Zhang and X.W. also contributed to data collection and reduction. A.W.H. and H.I. contributed to collecting and reducing Keck data. A.C.L., R.C. and R.R. contributed to collecting and reducing GTC data. Z.Q., S.L. and M.L. contributed to utilization of Gaia data. Y.Z., G.Z., Y.C. and X.C. contributed to the implementation of LAMOST. All contributed to the paper in various forms. The authors declare no competing interests.Attached Files
Accepted Version - 1911.11989.pdf
Supplemental Material - 41586_2019_1766_Fig3_ESM.jpg
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Supplemental Material - 41586_2019_1766_Tab1_ESM.jpg
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Supplemental Material - 41586_2019_1766_Tab3_ESM.jpg
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Additional details
- Alternative title
- A wide B star-black hole binary discovered directly through radial-velocity monitoring observation
- Eprint ID
- 100160
- Resolver ID
- CaltechAUTHORS:20191203-081807926
- 11988101
- National Natural Science Foundation of China
- 11425313
- National Natural Science Foundation of China
- 11773015
- National Natural Science Foundation of China
- 11333004
- National Natural Science Foundation of China
- U1838201
- National Natural Science Foundation of China
- 11603010
- National Natural Science Foundation of China
- 11690024
- National Natural Science Foundation of China
- U1531118
- National Natural Science Foundation of China
- 11603035
- National Natural Science Foundation of China
- 11733009
- National Natural Science Foundation of China
- 11325313
- National Natural Science Foundation of China
- 11633002
- National Natural Science Foundation of China
- 2019YFA0405504
- National Key Research and Development Program of China
- 2016YFA0400804
- National Key Research and Development Program of China
- 2016YFA0400803
- National Key Research and Development Program of China
- 2016YFA0400704
- National Key Research and Development Program of China
- AYA2017-83216-P
- Ministerio de Economía, Industria y Competitividad (MINECO)
- 2015/19/B/ST9/01099
- National Science Centre (Poland)
- 2018/30/A/ST9/00050
- National Science Centre (Poland)
- National Development and Reform Commission
- National Astronomical Observatories, Chinese Academy of Sciences (NAOC)
- W. M. Keck Foundation
- Created
-
2019-12-04Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department