| Term: | Compact binary stars |
| Definition: |
A binary star system which is composed of a collapsed object (degenerate dwarf, neutron star, or black hole) in orbit with a low-mass (≤ 0.5 M_sol) secondary star, wherein the collapsed star accretes matter from its companion. These two objects form a binary system of overall dimensions 10^6 km with an orbital period of only hours or less. |