Recycled pulsars

Pulsars that have undergone a binary history have come to be known as “recycled pulsars”. The very first binary pulsar to be discovered-the Hulse–Taylor pulsar-provided evidence for such a recycling. It is now widely accepted that the first-born neutron star dies a natural death as a pulsar due to its period lengthening. But eventually, it is spun back into life, once again, when it accretes matter and angular momentum from its companion. Such a spin up continues till the neutron star attains an “equilibrium period”, which is determined by the strength of its magnetic field and the accretion rate. This article will attempt to give a historical perspective of how the various steps in the evolution of such a recycled neutron star were understood.