A Model for the Braking Indices of Pulsars

Stars known as pulsars are generally modeled as magnetized spheres made of neutrons with high rotation frequency. It is known that such stars are spinning down and this braking is measured by a parameter, n, known as braking index. For the canonical model such parameter should have a single value for all pulsars: n = 3. However, from observations it is known that n diverges from 3. In this work, differently from the canonical model, we have hypothesized the existence of a variation of the moment of inertia of the star through a time-varying radius. Using energy conservation we find the values for the variation of the radius of our pulsar sample. Our results indicate that it may be reasonable to consider that the radius of pulsars can be changing with time.