Have neutron stars a dark matter core?

TL;DR

This paper proposes that certain neutron stars with unusual mass and radius measurements may contain dark matter cores, offering a new way to investigate dark matter properties through astrophysical observations.

Contribution

It introduces a novel hypothesis that dark matter cores inside neutron stars can explain their atypical properties, linking astrophysical data to dark matter research.

Findings

Mass-radius measurements can be explained with a nuclear matter equation of state plus a dark core.

Dark matter cores can vary in size within neutron stars, affecting their observable properties.

Future observations can test the dark matter core hypothesis.

Abstract

Recent observational results for the masses and radii of some neutron stars are in contrast with typical observations and theoretical predictions for "normal" neutron stars. We propose that their unusual properties can be interpreted as the signature of a dark matter core inside them. This interpretation requires that the dark matter is made of some form of stable, long-living or in general non-annihilating particles, that can accumulate in the star. In the proposed scenario all mass-radius measurements can be explained with one nuclear matter equation of state and a dark core of varying relative size. This hypothesis will be challenged by forthcoming observations and could eventually be a useful tool for the determination of dark matter.