Impact of accretion on the statistics of neutron star masses

TL;DR

This study analyzes the mass distribution of neutron stars in binary systems, revealing that millisecond pulsars are generally more massive than less recycled pulsars due to accretion effects, using statistical and simulation methods.

Contribution

It introduces a statistical approach combining bootstrap and Monte Carlo simulations to accurately determine neutron star mass distributions and quantify accretion effects.

Findings

MSPs have an average mass of 1.45 solar masses.

Less recycled pulsars have an average mass of 1.31 solar masses.

MSPs are heavier by approximately 0.13 solar masses due to accretion.

Abstract

We have collected the parameter of 38 neutron stars (NSs) in binary systems with spin periods and measured masses. By adopting the Boot-strap method, we reproduced the procedure of mass calculated for each system separately, to determine the truly mass distribution of the NS that obtained from observation. We also applied the Monte-Carlo simulation and introduce the characteristic spin period 20 ms, in order to distinguish between millisecond pulsars (MSPs) and less recycled pulsars. The mass distributions of MSPs and the less recycled pulsars could be fitted by a Gaussian function as $\rm 1.45\pm0.42 M_{\odot}$ and $\rm 1.31\pm0.17 M_{\odot} (\rm with ~ 1\sigma)$ respectively. As such, the MSP masses are heavier than those in less recycled systems by factor of $\rm \sim 0.13M_{\odot}$, since the accretion effect during the recycling process.