A fast pulsar in radio nebula CTB80

A fast pulsar with period of 39.5 milliseconds has been discovered in the peculiar combination nebula CTB80. This nebula has been proposed as the remnant of a possible historical supernova in ad 1408 (refs 1–3), but we argue that neither the nebula nor the new pulsar is linked to this supernova, which is in any case of doubtful veracity4. We suggest instead that the pulsar is at least 10,000 years old and that the observed features in the nebula are the result of the pulsar ploughing through the medium at ˜ 300 km s−1. In contrast to the other young pulsars, this pulsar has a smaller magnetic field strength and is consequently underluminous. We argue that this pulsar is more typical of young pulsars in general, a hypothesis that raises fundamental questions about the birth and evolution of pulsars.