Post-Supernova Accretion of Light Elements onto a New-Born Neutron Star and NS 1987A

TL;DR

This study models the early accretion of light elements onto a newborn neutron star, revealing conditions under which these elements can be accumulated without explosive nuclear reactions, aiding understanding of young neutron star atmospheres.

Contribution

It introduces a detailed simulation of light element accretion onto neutron stars using MESA, highlighting conditions that prevent nuclear explosions and explaining observed atmospheric compositions.

Findings

Significant accretion of light elements is possible without triggering explosions.

Accreted densities can reach up to 10^9 g/cc.

Supports the presence of light elements in young neutron star atmospheres.

Abstract

We model early accretion of light elements, He, C, and O, onto a new-born neutron star using the public stellar evolution code MESA, simulating what may happen during the first few years of its life. We find that, under the appropriate conditions, significant amounts of these elements can be accreted up to densities of 10^9 g/cc without triggering a nuclear explosion that would convert them into heavy elements. These results help to understand observations that favor light elements in the atmospheres of young cooling neutron stars, as the one found in the supernova remnant Cassiopeia A, and also add support to the recent indications for the presence of a neutron star, NS 1987A, in the remnant of SN 1987A.