We investigate constraints on neutron star structure arising from the assumptions that neutron stars have crusts , that recent calculations of pure neutron matter limit the equation of state of neutron star matter near the nuclear saturation density , that the high-density equation of state is limited by causality and the largest high-accuracy neutron star mass measurement , and that general relativity is the correct theory of gravity .
We explore the role of prior assumptions by considering two classes of equation of state models .
In a first , the intermediate- and high-density behavior of the equation of state is parameterized by piecewise polytropes .
In the second class , the high-density behavior of the equation of state is parameterized by piecewise continuous line segments .
The smallest density at which high-density matter appears is varied in order to allow for strong phase transitions above the nuclear saturation density .
We critically examine correlations among the pressure of matter , radii , maximum masses , the binding energy , the moment of inertia , and the tidal deformability , paying special attention to the sensitivity of these correlations to prior assumptions about the equation of state .
It is possible to constrain the radii of 1.4 ~ { } \mathrm { M } _ { \odot } neutron stars to a be larger than 10 km , even without consideration of additional astrophysical observations , for example , those from photospheric radius expansion bursts or quiescent low-mass X-ray binaries .
We are able to improve the accuracy of known correlations between the moment of inertia and compactness as well as the binding energy and compactness .
We also demonstrate the existence of a correlation between the neutron star binding energy and the moment of inertia .