Cygnus X-1 and LMC X-3 are black holes if the masses of the unseen companions perhaps may be

Question

Quizplus · Accepted Answer

Cygnus X-1 and LMC X-3 are considered black holes based on the behavior and properties of their companion stars. The mass of the black hole is estimated by studying the motion of the companion star, which must be in a tight orbit with the black hole. Since both systems are thought to have stellar companions that are relatively massive (around 10 solar masses), the black holes themselves must be more massive than 3 solar masses to explain the observed behavior. Therefore, choice B is the best answer.

Cygnus X-1 and LMC X-3 Are Black Holes If the Masses