|Low-mass x-ray binary stars
A member of one of the two main classes of X-ray binary systems where one of the components is a neutron star or black hole and the other component a low-mass star with a spectral type A or later. LMXBs mainly emit soft X-rays. The ratio of their optical to X-ray luminosities is less than 0.1. They belong to old stellar populations with ages 5-15 x 10^9 years and are found in globular clusters and in the bulge of our Milky Way galaxy; some are also found in the disk. Hercules X-1 is an example of LMXBs.