The key to identifying a black hole candidate in a binary system is that:
A)one of the two stars cannot be seen.
B)the unseen companion in the system must have a sufficiently high mass.
C)the unseen star is a contact binary.
D)the system must be a very strong source of radio emissions.
E)the visible companion must be an evolving main sequence or giant star.

Question

Quizplus · Accepted Answer

The key to identifying a black hole candidate in a binary system is that the unseen companion in the system must have a sufficiently high mass. This is because black holes are formed from the collapse of massive stars, so the presence of a high-mass companion is a strong indication that the unseen object could be a black hole. The other options may or may not be present in a binary system with a black hole candidate. The presence of a black hole candidate in a binary system can be inferred by observing the behavior of the visible companion star. If the companion star is being orbited by an unseen object with a sufficiently high mass, and if the orbits of the two objects suggest that the unseen object is compact and non-luminous, then the most likely explanation is that the unseen object is a black hole.

The Key to Identifying a Black Hole Candidate in a Binary