Statistical theory of thermal evolution of neutron stars - II. Limitations on direct Urca threshold

TL;DR

This paper uses a statistical approach to analyze neutron star thermal evolution, constraining the direct Urca process threshold and broadening based on observational data, suggesting specific values for the threshold parameters and neutron star mass.

Contribution

It introduces a statistical method to constrain the direct Urca neutrino emission threshold and broadening in neutron star cores using observational data.

Findings

Most likely alpha between 0.08 and 0.10

Direct Urca process opens at neutron star mass 1.6-1.8 M_sun

Constraints on the threshold parameters based on thermal evolution observations

Abstract

We apply our recently suggested statistical approach to thermal evolution of isolated neutron stars and accreting quasistationary neutron stars in X-ray transients for constraining the position and relative broadening alpha of the direct Urca threshold of powerful neutrino emission in neutron star cores. We show that most likely explanation of observations corresponds to alpha = 0.08 - 0.10 and to the neutron star mass, at which the direct Urca process is open, M_D = (1.6 - 1.8) M_sun.