SIMBAD references

The analysis of some braking mechanisms for neutron stars was carried out to determine the sign of the second derivative of the pulsar spin period. This quantity is an important parameter for calculations of the braking index n. It is shown that this derivative can be positive and lead to a decrease in n. It is necessary to correct the methods of calculations of n used at this moment because they are based as a rule on the suggestion on the constancy of pulsar parameters (magnetic fields, angles between some axes and so on). The estimations of corrections to braking indices are obtained. It is shown that these corrections can be noticeable for pulsars with long periods and their small derivatives.