The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We use radio astrometry to refine the distance to the black hole X-ray binary Cygnus X-1, which we find to be \(2.22^{+0.18}_{-0.17}\) kilo...

Cygnus X-1 contains a 21-solar mass black hole -- implications for massive star winds

10.48550/arxiv.2102.09091