PSR B1259 63 LS 2883

PSR B1259-63 is a pulsar and member of an eclipsing binary star system with the blue B2e-class star SS 2883. The pair has an eccentric orbit that is inclined to the line of sight from Earth by about 36°, leading to a 40-day-long eclipse each time the pulsar passes behind the star. The pulsar has a period of about 48 ms and a luminosity of 8.3 × 10³⁵ erg/s. It emits very high energy gamma rays that vary on a time scale of several days.

The star SS 2883 has about 10 solar masses and is 6 solar radii in size. The rate of rotation is about 280 km/s at the equator, or 70% of the breakup velocity.