The properties of neutron stars are determined by the nature of the matter that they contain. These properties can be constrained by measurements of the star’s size. We obtain stringent constraints on neutron-star radii by combining multimessenger observations of the binary neutron-star merger GW170817 with nuclear theory that best accounts for density-dependent uncertainties in the equation of state. We construct equations of state constrained by chiral effective field theory and marginalize over these using the gravitational-wave observations. Combining this with the electromagnetic observations of the merger remnant that imply the presence of a short-lived hypermassive neutron star, we find that the radius of a 1.4 M_⊙ neutron star is \({R}_{1.4{M}_{\odot }}={11.0}_{-0.6}^{+0.9}\ {\rm{km}}\) (90% credible interval). Using this constraint, we show that neutron stars are unlikely to be disrupted in neutron star–black hole mergers; subsequently, such events will not produce observable electromagnetic emission.

中子星的性质取决于它们所含物质的性质。这些特性可以通过测量恒星的大小来约束。通过将二元中子星合并GW170817的多信使观测结果与核理论相结合，获得对中子星半径的严格约束，该理论最能说明状态方程中与密度有关的不确定性。我们构造了受手性有效场理论约束的状态方程，并利用引力波观测将这些方程边缘化。与暗示昙花一现hypermassive中子星的存在合并剩余的电磁观测相结合，我们发现，1.4的半径 中号_⊙中子星\（{R} _ {1.4 {M} _ {\ odot}} = {11.0} _ {-0.6} ^ {+ 0.9} \ {\ rm {km}} \）（90％可信区间）。利用这种约束，我们表明中子星-黑洞合并中的中子星不太可能被破坏。随后，此类事件将不会产生可观察到的电磁辐射。