Pulsars and Ancient Chinese Records of Supernova Explosions

Abstract

THE discovery of a pulsar near the Crab Nebula with an apparently increasing period of 0.03309 s (F. D. Drake at the fourth Texas symposium on relativistic astrophysics, 1968) and the earlier detection of another short period pulsar (PSR 0833–45) at the site of the supernova remnant Vela X (ref. 1) seem to support the idea that pulsars are associated with the end product of supernova explosions, presumably the neutron stars. The rate of pulsation is fastest when the star is young but gradually slows down to ∼ 1 s. To test further such a hypothesis, it will be interesting to look for more pulsars associated with supernovae of known age. No doubt radio astronomers have already started searching for fast pulsars at the sites of two other well known historical supernovae, Tycho and Kepler. Examination of ancient oriental records on suspected supernovae events, however, suggests some more promising candidates. They were at the explosion as bright as or brighter than the Crab supernova. Hence they could be close enough for pulsars associated with them to be within the detectable range.