Relativistic mean-field model for the ultracompact low-mass neutron star HESS J1731-347
S. Kubis, W. Wójcik, David Alvarez-Castillo, Noemi Zabari
Abstract
The recent observation of the object HESS J1731-347 suggests the existence of a very light and very compact neutron star, which is a challenge for commonly used equations of state for dense matter. In this work we present a relativistic mean-field model enriched with isovector and isoscalar meson crossing terms. These interactions dominate the behavior of the symmetry energy and account for the small radius. The proposed model fulfills the recent constraints concerning the symmetry energy slope and the state-of-the-art compact star constraints derived from the NICER measurements of the pulsars PSR $\mathrm{J}0030+0451$ and PSR $\mathrm{J}0740+6620$, as well as from the GW170817 event and its associated electromagnetic counterparts AT2017gfo/GRB170817A.