SIMBAD references

We have observed time-variations in the profiles of several infrared emission lines from the X-ray binary, Cyg X-3, which is believed to consist of a Wolf-Rayet star and a compact object. We conclude that the variations are due to the orbital motion of the Wolf-Rayet star and derive a mass function for Cyg X-3 of 2.3M_☉. Assuming reasonable values for the mass of the Wolf-Rayet star and the inclination of the system, we obtain a range of masses 7-40M_☉ for the compact object, with a most likely value of 17M_☉. This strongly suggests that the compact component of Cyg X-3 is a black hole.