Information about Vela X-1

The data given were obtained by the Japanese Tenma satellite (Sato, et al. 1986). Astrophysicists have also determined the following that you and your students may find interesting and useful.

• The system is composed of a neutron star in orbit around a B supergiant star that is about 34 times the size of the Sun.

• The observed asymmetric light curve is due to enhanced X-ray scattering off of an extended region, which trails the neutron star. This region is created by X-ray ionization of the accreting material.

• It's measured orbital velocity is 280 km/sec.