Pulsar PSR B1259-63 is a radio pulsar, which means most of the time it emits only radio waves. The binary system lies in the general direction of the Southern Cross about 5000 light-years away.

PSR B1259-63 orbits a ‘Be’ star named SS 2883, which is bright and visible to amateur astronomers, seen here in this image. ‘Be’ stars, so named because of certain spectral characteristics, tend to be a few times more massive than our Sun and rotate at astonishing speeds.

They rotate so fast that their equatorial region bulges and they become flattened spheres, and some fling off gas which settles into an equatorial ring around the star.

The pulsar plunges into the Be star’s ring twice during its 3.4-year elliptical orbit and it is during the plunges that X-rays and gamma rays are emitted.