Tables of Hyperonic Matter Equation of State for Core-Collapse Supernovae
Feb, 2008
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Abstract: (arXiv)
We present sets of equation of state (EOS) of nuclear matter including hyperons using an SU_f(3) extended relativistic mean field (RMF) model with a wide coverage of density, temperature, and charge fraction for numerical simulations of core collapse supernovae. Coupling constants of Sigma and Xi hyperons with the sigma meson are determined to fit the hyperon potential depths in nuclear matter, U_Sigma(rho_0) ~ +30 MeV and U_Xi(rho_0) ~ -15 MeV, which are suggested from recent analyses of hyperon production reactions. At low densities, the EOS of uniform matter is connected with the EOS by Shen et al., in which formation of finite nuclei is included in the Thomas-Fermi approximation. In the present EOS, the maximum mass of neutron stars decreases from 2.17 M_sun (Ne mu) to 1.63 M_sun (NYe mu) when hyperons are included. Hyperon effects are found to be small in prompt phase of supernova explosions, since the temperature and density do not reach the region of hyperon mixture, where the hyperon fraction is above 1 %, (T > 40 MeV or rho_B > 0.4 fm^{-3}). We also discuss the effects of pions in neutron stars and supernova explosions.Note:
- 21 pages, 5 figures
- nuclear matter
- equation of state
- hyperon: matter
- mean field approximation
- symmetry: SU(3)
- supernova
- coupling constant: (hyperon sigma meson)
- Xi
- Sigma
- neutron star: mass
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