Temperature dependent variation of pulsar periods

Changes in the radii of neutron stars due to variations in core temperature are studied qualitatively in a simple model. The resulting irregular changes in pulsar periods are compared with observed values. For the millisecond pulsar PSR 1937 + 214 the random changes in period due to temperature variation is estimated to be of the order of 10^-14s yr^-1 which is two orders of magnitude smaller than the steady variation due to loss of energy by radiation.