2021MNRAS.502.1925L

In this letter, we note that the observed in the LIGO/Virgo experiment ratio of the detection rate of black holes to the rate of detection of binary neutron stars requires the assumption of a 'conservative' collapse of massive stars into a black hole: almost all the mass of the collapsing star goes under the horizon. This is consistent with the large masses of black holes detected by LIGO/Virgo. On the other hand, the assumption of a small loss of matter during the collapse into a black hole is in good agreement with the small eccentricity of single-lined binaries. At the same time, the absence of X-rays from most black holes in binary systems with blue stars is explained. We argue that three sets of LIGO/Virgo observations and data on the single-lined binary with a candidate black hole component confirm the scenario of the evolution of massive field binaries.