Speaker
Description
The recent observation of the object HESS J1731-347 by Doroshenko et al. (2022) suggests the existence of a very light and very compact neutron star.
In order to quantify this result, the authors of this study consider a family of chiral equation of state (EOS) models that can reproduce the properties of the aforementioned object as well as to fulfill state-of-the-art compact stars constraints derived from NICER measurements of PSR J0030+0451 and PSR J0740+6620 pulsars as well as from the GW170817 event and its associated electromagnetic counterparts AT2017gfo and GRB170817A. In this contribution, we present two alternative EoS equally valid, a) a pure hadronic relativist mean field approach featuring sigma-delta meson interactions leading to a softening of the EoS in a moderate range of densities, and b) a hybrid equation of state that produces hybrid compact stars of low mass therefore very compact and whose hadronic matter is rather stiff. For simplicity, their quark matter core is described by the constant speed of sound approach which is well compatible with some more detailed but complex superconducting quark matter descriptions.
