The influence of the enhanced vector meson sector on the properties of the matter of neutron stars

A Statistical Approach to Neutron Stars' Crust-Core Transition Density and Pressure

In this paper, a regression model between neutron star crust-core pressure and the symmetry energy characteristics was estimated using the Akaike information criterion and the adjusted coefficient of determination Radj2. The most probable value of the transition density, which should characterize the crust-core environment of the sought physical neutron star model, was determined based on the obtained regression function. An anti-correlation was found between this transition density and the main characteristic of the symmetry energy, i.e., its slope L.

Forms of the Symmetry Energy Relevant to Neutron Stars

The symmetry energy is an invaluable tool for studying dense nuclear matter. Unfortunately, its definition is somewhat implicit, and therefore, phenomenological methods are necessary to describe experimental facts. This paper discusses the differences arising from the use of Taylor series expansion and Padé approximation to determine theoretically the symmetry energy and the possible consequences for neutron stars. For this purpose, a form of the nuclear matter equation of state that explicitly depends on the symmetry energy is used. The obtained results point out that the applied approximations lead to modifications of the equilibrium proton fractions and equation of state, especially in their high-density limit. However, this effect is small near the saturation density n 0 .