2005PASJ...57..365T

A model of pulsar that has a magnetized core is presented and the behavior in evolution of spin and luminosity is analyzed. The stars are supposed to be polytropes, thereby rendering all physical quantities calculable with any desired precision. The mechanism of energy dissipation consists of interactions between the magnetic core and a shell as well as the magnetic dipole radiation. Owing to a huge electronic conductivity, the interaction between the core and the shell can be so weak that differential rotation of the two stellar components is allowed over very long terms. Identifying the rotation period of the magnetized core as the pulse-period of pulsar, we find that there exists an almost stationary era in the evolution of the pulse-period, during which the luminosity is dominated not by the dipole radiation but by the core-shell interaction. Implications of the model on anomalous X-ray pulsars 1E 1841- 045 and 1E 2259+586 are discussed.