Question

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 star is a contact binary. c. the visible companion must be an evolving main sequence or giant star. d. the system must be a very strong source of radio emissions.

Answer 1

D. Black holes due to their nature are extremely hard to directly observe, they do however emit radio emissions. We can use clues from the surrounding space to detect them. A is not correct as black holes do not necessarily block other stars light. B is false because contact binaries are not exclusive formations from black holes. C is false because not all stars create black holes, giant stars may but finding the star doesn’t mean you’ve found a black hole yet.