Galactic population of black holes in detached binaries with low-mass stripped helium stars: The case of LB-1 (LS V+22 25)

© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. We model the Galactic population of detached binaries that harbour black holes with 0.5-1.7 M companions - remnants of case B mass exchange that rapidly cross Hertzsprung gap after the termination of the Roche lobe overflow or as He-shell burning stars. Several such binaries can be currently present in the Galaxy. The range of MBH in them is about 4-10 M, and the orbital periods are tens to hundreds of days. The unique black hole binary LB-1 fits well into this extremely rare class of double stars