Birth accelerations of neutron stars

Abstract

We suggest that neutron stars experienced at birth three related physical changes, which may originate in magneto-rotational instabilities: (i) an increase in period from the initial value P_0 to the current value P_s, implying a change of rotational energy ΔE_rot; (ii) an exponential decay of its magnetic field from the initial value B_0 to the current surface value B_s, implying a change of radiative energy ΔE_rad; and (iii) an increase of space velocity from the initial value v_0 to the current value v, implying a change of kinetic energy ΔE_kin. These changes are assumed to be connected by ΔE_rad + ΔE_kin =ΔE_rot. This means that the radiation loss and increase of kinetic energy are both at the expense of a rotational energy loss. It is shown that this energy conversion occurs during times of order of 10^(-4) s if the neutron stars are born with magnetic fields in the range of 10^(15)-10^(16) G and initial periods in range 1-20 ms. It is shown that the birth accelerations of neutron stars are of the order of 10^(8) g.

arXiv commentTo be published in the Proceedings of IAU Symposium 291 "Neutron Stars and Pulsars: Challenges and Opportunities after 80 years", Cambridge University Press