Massive neutron stars with hyperonic core : a case study with the IUFSU model

Abstract

The recent discoveries of massive neutron stars, such as PSR J$0348+0432$ and PSR J$1614-2230$, have raised questions about the existence of exotic matter such as hyperons in the neutron star core. The validity of many established equations of states (EoS's) like the GM1 and FSUGold are also questioned. We investigate the existence of hyperonic matter in the central regions of massive neutron stars using Relativistic Mean Field (RMF) theory with the recently proposed IUFSU model. The IUFSU model is extended by including hyperons to study the neutron star in $\beta$ equilibrium. The effect of different hyperonic potentials, namely $\Sigma$ and $\Xi$ potentials, on the EoS and hence the maximum mass of neutron stars has been studied. We have also considered the effect of stellar rotation since the observed massive stars are pulsars. It has been found that a maximum mass of $1.93M_{\odot}$, which is within the 3$\sigma$ limit of the observed mass of PSR J$0348+0432$, can be obtained for rotating stars, with certain choices of the hyperonic potentials. The said star contains a fair amount of hyperons near the core.