Thermodynamic instabilities and statistical effects in protoneutron stars

[摘要] We investigate the physical properties of the protoneutron stars in the framework of a relativistic mean-field model and we study the finite-temperature equation of state in β-stable matter at fixed entropy per baryon, in the presence of hyperons, Δ-isobar resonances and trapped neutrinos. In this context, we study the possible presence of thermodynamic instabilities and a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. We show that such statistical effects could play a crucial role in the structure and in the evolution of the protoneutron stars.

[发布机构] Dipartimento di Fisica, Università di Torino, Torino; I-10126, Italy^1;Department of Applied Science and Technology, Politecnico di Torino, Torino; I-10129, Italy^2;INFN, Sezione di Torino, Torino; I-10125, Italy^3

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] Asymmetric nuclear matter;Baryon density;Equation of state;Finite temperatures;Mechanical instabilities;Relativistic mean fields;Statistical effects;Thermodynamic instability