Tags: Star.
Vela X-1 is a pulsing eclipsing high-mass X-ray binary (HMXB) system associated with the Uhuru source 4U 0900-40 and the supergiant star HD 77581. The X-ray emission of the neutron star is caused by the capture and accretion of matter from the stellar wind of the supergiant companion. Vela X-1 is the prototypical detached HMXB.The orbital period of the system is 8.964 days with the neutron star being eclipsed for about two days of each orbit by HD 77581.