The role of binding energies of neutron stars on the accretion driven evolution

TL;DR

This paper emphasizes the importance of considering neutron star binding energy in models of binary millisecond pulsar evolution, showing it significantly affects accreted mass estimates and constrains dense matter equations of state.

Contribution

It introduces the impact of neutron star binding energy into accretion models, highlighting its significance in understanding pulsar evolution and dense matter properties.

Findings

Binding energy significantly affects mass accretion estimates.

Different equations of state yield varying accreted mass values.

Inclusion of binding energy improves binary pulsar evolution models.

Abstract

Millisecond pulsars are believed to descend from low mass x-ray binaries. Observable parameters of binary millisecond pulsars e.g. mass of the pulsar, mass of the companion, spin period of the pulsar, orbital period, orbital eccentricity etc are used to probe the past accretion history of the millisecond pulsars. But unfortunately in these studies, binding energy of the neutron star is not considered commonly. We show that the effect of the binding energy is significant in the estimation of the amount of mass accretion and thus should be incorporated in models for binary evolutions. Moreover, different Equations of State for dense matter give different values for the accreted mass for the same amount of increase in the gravitational mass of the neutron star implying the need of constraining dense matter Equations of State even to understand the spin-up procedure properly.