The search for black holes has so far turned up some fairly convincing stellar-sized candidates in binary star systems. What observations could you make to distinguish whether the unseen object in one of these systems is a black hole or a neutron star?

Th similarities between the black hole and the neutron star is that they are formed from dead (dying) starts. But they come from different parent stars, if the parent star is 1.4 times the mass of the sun, a neutron star will be formed, but if the parent star is twice the mass of the sun a black hole is formed.

Explanation:

A black hole is defined as an area of space whereby the matter is so compacted that nothing can escape from it. This area is called event horizon. Black holes are formed when an enormous star dies in z supernova. They weigh at least twice the sun's mass, and their mass is directly proportional to their radii.

Neutron stars are created during supernova and maintained by a neutron called degeneracy pressure. Neutron star has a small radius, typically 30 km, with a very high density made up of compacted neutrons.