2021MNRAS.502.3476S -
Mon. Not. R. Astron. Soc., 502, 3476-3490 (2021/April-2)
Equation of state of hot dense hyperonic matter in the Quark-Meson-Coupling (QMC-A) model.
STONE J.R., DEXHEIMER V., GUICHON P.A.M., THOMAS A.W. and TYPEL S.
Abstract (from CDS):
We report a new equation of state (EoS) of cold and hot hyperonic matter constructed in the framework of the quark-meson-coupling (QMC-A) model. The QMC-A EoS yields results compatible with available nuclear physics constraints and astrophysical observations. It covers the range of temperatures from T = 0 to 100 MeV, entropies per particle S/A between 0 and 6, lepton fractions from YL = 0.0 to 0.6, and baryon number densities nB = 0.05-1.2 fm–3. Applications of the QMC-A EoS are made to cold neutron stars (NSs) and to hot proto-neutron stars (PNSs) in two scenarios: (i) lepton-rich matter with trapped neutrinos (PNS-I) and (ii) deleptonized chemically equilibrated matter (PNS-II). We find that the QMC-A model predicts hyperons in amounts growing with increasing temperature and density, thus suggesting not only their presence in PNS but also, most likely, in NS merger remnants. The nucleon-hyperon phase transition is studied through the adiabatic index and the speed of sound cs. We observe that the lowering of (cs/c)2 to and below the conformal limit of 1/3 is strongly correlated with the onset of hyperons. Rigid rotation of cold and hot stars, their moments of inertia and Kepler frequencies are also explored. The QMC-A model results are compared with two relativistic models, the chiral mean field model (CMF), and the generalized relativistic density functional (GRDF) with DD2 (nucleon-only) and DD2Y-T (full baryon octet) interactions. Similarities and differences are discussed.
Abstract Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
dense matter - equation of state - stars: evolution - stars: neutron
Simbad objects:
7
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