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

Article

关键词: BLANKETED MODEL ATMOSPHERES;    X-RAY BINARIES;    M-CIRCLE-DOT;    STELLAR EVOLUTION;    FUNDAMENTAL PLANE;    ACCRETION FLOWS;    MASS;    EMISSION;    ISOCHRONES;    SPECTRUM;   

DOI  :  10.1038/s41586-019-1766-2

来源: SCIE

【 摘 要 】

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(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 taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Ha 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.

【 授权许可】

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