No signature of the orbital motion of a putative 70 solar mass black hole in LB-1

Understand

Liu et al.

• (2019) recently reported the detection of a 68 [+11/-13] solar mass (Msun) black hole (BH) paired with an 8.2 [+0.9/-1.2] Msun B-type sub-giant star in the 78.9-day spectroscopic binary system LB-1.
• Such a black hole is over twice as massive as any other known stellar-mass black hole with non-compact companions2 and its mass approaches those that result from BH-BH coalescences that are detected by gravitational wave interferometers.
• Its presence in a solar-like metallicity environment challenges conventional theories of massive binary evolution, stellar winds and core-collapse supernovae, so that more exotic scenarios seem to be needed to explain the existence and properties of LB-1.