Binary star system. Artwork of the two stars of a binary star system seen from an alien planet. A giant blue star (upper left) is accompanied by a neutron star (centre right). The blue star burns brightly as a massive, short-lived star that may use up its nuclear fuel in a few million years. It has a strong stellar wind of material being lost to space. The wind has formed a shock wave around the small, super-dense neutron star that will capture the material in this process which is called bow-shock accretion. A neutron star is the remnant of a massive star that collapsed under its own gravity after its sustaining nuclear reactions ceased. Around half of all stars form binaries.