Question

when a star is oribiting a compact object, how can we tell if its a neutron star, or black hole?
neutron stars are visibly detectable whereas black holes are not.
x - rays can be detected around a neutron star, but no radiation is detected around black hole.
stars orbiting a neutron star are considerable smaller than those orbiting a black hole.
black holes produce bursts of energy whereas neutron stars do not.
in addition to the x - rays, neutron stars will also emit detectable bursts of energy whereas black holes do not.

Explanation:

• Neutron stars have a surface. When matter accretes onto a neutron star, it hits the surface and can produce detectable bursts of energy (like X - ray bursts due to nuclear reactions on the surface).
• Black holes have no surface. Matter falling into a black hole crosses the event horizon and does not produce such surface - related bursts of energy (although there can be accretion disk emissions, but not the same kind of surface - based bursts as neutron stars).

Answer:

In addition to the X - Rays, neutron stars will also emit detectable bursts of energy whereas black holes do not.