Vela pulsar
Vela pulsar
The second optical pulsar to be discovered, the optical flashes being detected in 1977. With a brightness of only about 26 magnitudes – one of the faintest optical bodies to be detected – it is considerably fainter than the optical pulsar in the Crab nebula, although at a distance of about 500 parsecs it is four times nearer. It was already known to emit pulses of radio emission in a period of 0.089 seconds and pulses of gamma rays twice every revolution. At gamma-ray wavelengths it is the brightest object in the sky. The optical pulses were found by sampling the light from a field only five arc seconds across, centered on the accurate radio position of the pulsar, and folding the data to the precise radio period.Like other pulsars, the Vela pulsar is gradually slowing down in its rotation rate. Several brief and temporary increases in rotation rate – glitches – have however been observed since 1969 (see pulsar). It is a young pulsar, some 10 000 years old, and (like the Crab pulsar) is one of the very few to be associated with a supernova remnant. The remnant, Vela-X, has been observed at X-ray, XUV, optical, and radio wavelengths.