Long-lasting accretion-powered chemical heating of millisecond pulsars

TL;DR

This paper investigates how magnetic fields in neutron-star cores can sustain chemical heating in millisecond pulsars, potentially maintaining their warmth for over a billion years without relying on rotochemical heating.

Contribution

It introduces a new mechanism where magnetic fields suppress proton superconductivity, enabling ongoing chemical heating in MSPs.

Findings

Magnetic fields destroy proton superconductivity in neutron-star cores.

Chemical reactions convert stored energy into heat, sustaining MSP temperature.

MSPs can remain warm for over a billion years due to this process.

Abstract

We analyze the effect of magnetic field in superconducting neutron-star cores on the chemical heating of millisecond pulsars (MSPs). We argue that the magnetic field destroys proton superconductivity in some volume fraction of the stellar core, thus allowing for unsuppressed non-equilibrium reactions of particle mutual transformations there. The reactions transform the chemical energy, accumulated by a neutron star core during the low-mass X-ray binary stage, into heat. This heating may keep an NS warm at the MSP stage (with the surface temperature $\sim 10^5\,\rm K$) for more than a billion of years after ceasing of accretion, without appealing to the rotochemical heating mechanism.