Adiabatic evolution of hadronic neutron stars

Abstract

In this paper we compute several structural properties of static and rotating neutron stars, considering both rigid and differential rotation. To this end, we use a finite-temperature beta-stable equation of state (EOS) extending the zero-temperature hadronic EOS derived by Fortin et al. (2017). We account for the formation of hyperons and the presence of a neutrino-trapped component. Our goal is to provide insights into the long-term evolution of a protoneutron star (PNS) formed after a core-collapse supernova (CCSN) or a remnant resulting from a binary neutron star merger (BNSM). The EOS is derived using a relativistic mean-field quantum many-body theory within the Hartree approximation. Coupling constants are determined using experimental data on hypernuclei and hypernuclear matter to better account for uncertainties in hyperon single-particle potentials. Our EOS models reproduce the typical features of cold neutron stars and PNSs for nucleonic and hyperonic compositions. In particular, they are consistent with measured masses (2.01 M_sun and 2.14 M_sun for PSR J0348+0432 and PSR J0740+6620) and dimensionless tidal deformabilities from GW170817. Thermal contributions act differently depending on composition and rotation state. Finally, our evolutionary scheme provides a simple way to interpret the long-term evolution of BNSM remnants or PNSs from CCSNe, complementing dynamical simulations unable to cover full evolutionary timescales.