| Popis: |
We present an analysis of hot and dilute isospin-asymmetric nuclear matter employing the temperature-dependent effective-relativistic mean-field theory (E-RMF). We consider nuclear matter to be homogeneous and study the equation of state (EoS) for densities, temperature, and asymmetry which are relevant for astrophysical simulations such as supernovae explosion and neutron-star crust. The two recently developed E-RMF parameter sets IOPB-I and G3 are used here to study various physical observables at finite temperatures. These sets are known to reproduce the nuclear matter properties, in agreement with various experimental and observational constraints. The effect of temperature is investigated in reference to the density-dependent free symmetry energy and its higher-order derivatives using the well-known parabolic approximation. The larger value of ${\ensuremath{\lambda}}_{\ensuremath{\omega}}$ cross coupling in G3 in addition to the $\ensuremath{\delta}$ meson coupling in G3 smoothen the free symmetry energy. Thermal effects on various state variables are examined at fixed temperature and isospin asymmetry by separating their $T=0$ and the finite-$T$ expressions. The thermal effects are governed by effective mass where larger effective mass corresponds to larger thermal contribution. The effect of temperature on isothermal and isentropic incompressibility is discussed, which is in harmony with various microscopic calculations. The liquid-gas phase-transition properties are examined in asymmetric matter in the context of different slope parameter and comparable symmetry energy in the IOPB-I and G3 set. The spinodal instability, binodal curve, and critical properties are found to be influenced by the slope parameter ${L}_{\mathrm{sym}}$. Finally, we consider a more realistic system (with the inclusion of electrons) and analyze the effect on instability and adiabatic index of isospin asymmetric nuclear matter. |
