Neutron star structure in an in-medium modified chiral soliton model

TL;DR

This paper models neutron star structure using an in-medium modified chiral soliton approach, deriving equations of state from nuclear phenomenology, and successfully reproduces observed neutron star masses.

Contribution

It introduces a novel in-medium modified chiral soliton model to describe neutron star matter, linking nuclear phenomenology with astrophysical observations.

Findings

Reproduces neutron star masses of 1.4 and 2 solar masses.

Derives equations of state consistent with nuclear saturation properties.

Provides extrapolations to high-density, asymmetric nuclear matter.

Abstract

We study the internal structure of a static and spherically symmetric neutron star in the framework of an in-medium modified chiral soliton model. The Equations of State describing an infinite and asymmetric nuclear matter are obtained introducing the density dependent functions into the low energy free space Lagrangian of the model starting from the phenomenology of pionic atoms. The parametrizations of density dependent functions are related to the properties of isospin asymmetric nuclear systems at saturation density of symmetric nuclear matter $\rho_0\simeq 0.16$~fm$^{-3}$. Our results, corresponding to the compressibility of symmetric nuclear matter in the range $250\,\mbox{MeV}\le K_0\le 270\,\mbox{MeV}$ and the slop parameter value of symmetry energy in the range $30\,\mbox{MeV}\le L_S\le 50\,\mbox{MeV}$, are consistent with the results from other approaches and with the experimental indications. Using the modified Equations of State, near the saturation density of symmetric nuclear matter $\rho_0$, the extrapolations to the high density and highly isospin asymmetric regions have been performed. The calculations showed that the properties of $\sim 1.4M_\odot$ and $\sim 2M_\odot$ neutron stars can be well reproduced in the framework of present approach.