X-ray binary stars are systems containing a normal star and a compact object in orbit around it. The compact object may be either a black hole or a neutron star. In these systems, there is a transfer of matter from the normal star towards the compact object, a process technically known as accretion. The compact object is usually surrounded by an accretion disc formed by the infalling flow of matter spiraling around it. The interaction between the accreted material and the huge gravitational field of the black hole or neutron star produces an intense heating of the disc and makes it radiate in X-rays, hence the name of X-ray binaries.
Design by Marc Ribó & Josep M. Paredes
Last updated: 2003 March 28