Studies on the Anomalous Rotation Observed in Millisecond Pulsars

球状星团M4中的毫秒脉冲星1620-26表现出异常大的脉冲频率二阶导数，这与其他脉冲定时参数一起产生了4*10^7的制动指数。Shibazaki和Mochizuki（1995，ApJ 438，288）提出，地壳-超流体耦合中的摩擦不稳定性（在临界温度以下）可能是脉冲星旋转这种极端行为的原因。为了验证这一假设，我们对老中子星再循环后的热演化和转动演化进行了数值计算。我们证实，地壳和超流体之间的摩擦不稳定性引起的内部摩擦的快速增长，可以产生一个非常大的二阶导数的地壳旋转速率，在PSR 1620-26中观察到的。通过<cr><-1><43>与PSR 1620-26中观测到的时间参数的比较，我们得到了内壳超流体的临界角速度差和转动惯量分别为ω_（-10）rad·s^和I_s-3.6*10^ g·cm ^2。Ω_<cr>和I_s的这些值在当前模型的预期范围内。我们发现，要解释PSR 1620-26的Ω_c，需要在地壳内有一个强的钉扎区。

The millisecond pulsar 1620-26 in the globular cluster M4 exhibits an unusually large second derivative of the pulse frequency, which togethr with the other pulse timing parameters yields a braking index of 4*10^7. Shibazaki and Mochizuki (1995, ApJ 438,288) have suggested a frictional instability in the crust-superfluid coupling, which sets in below a critical temperature, as a possible cause for this extreme behavior of the pulsar rotation. We have conducted numerical calculations for the thermal and rotational evolution of old neutron stars after being recycled in order to examine this suggestion. We confirm that the rapid growth in internal friction between the crust and the superfluid, caused by frictional instability, can produce an extremely large second derivative in the crust-rotation rate, as observed in PSR 1620-26. We obtain omega_<cr>-10 rad s^<-1> and I_s-3.6*10^<43> g cm^2 respectively for the critical angular-velocity difference and the moment of inertia of the inner crust superfluid from a comparison of our results with the timing parameters observed in PSR 1620-26. These values for omega_<cr> and I_s are in the range expected in current models. We find that a strong pinning region is required in the inner crust in order to explain OMEGA_c of PSR 1620-26.