Neutron Star Radii from Laboratory Experiments

TL;DR

This paper reviews the nuclear equation of state relevant for neutron star modeling, highlighting recent constraints on neutron star radii from laboratory experiments, nuclear theory, and astrophysical data.

Contribution

It synthesizes recent findings to constrain neutron star radii and emphasizes the importance of laboratory experiments in reducing uncertainties.

Findings

Neutron star radii are constrained between 12 km and 13 km.

Uncertainty mainly arises from the density range between nuclear saturation and twice that value.

Laboratory experiments can access the critical density interval to improve models.

Abstract

Our present knowledge of the nuclear equation of state is briefly reviewed in this article intended for a wider readership. Particular emphasis is given to the asymmetric-matter equation of state required for modeling neutron stars, neutron-star mergers, and r-process nucleosynthesis. Recent analyses based on combining information obtained from nuclear theory, heavy-ion collisions and astrophysical observations confine the obtained radii of the canonical 1.4-solar-mass neutron star to values between 12 km and 13 km. The remaining uncertainty is primarily related to missing information in the density interval between nuclear saturation density and about twice that value which, however, is accessible with laboratory experiments.