Abstract Based on the shell-model Monte Carlo method and random phase approximation theory, the neutrino energy spectrum (NES) and the electron capture (EC) of 56 Fe, 56Co, 56Ni, 56 Mn, 56Cr and 56V are investigated in presupernova surroundings. The results show that the EC rates are affected greatly at different densities and temperatures. The rates increase greatly and even exceed six orders of magnitude at lower temperature. On the other hand, the NES is very sensitive to stellar temperature and electron energy. The higher the temperature and the lower the electron energy, the larger the influence on NES is. For example, the maxima of NES in the ground state are 9.02, 160, 80, 24.01, 0.44, 1.42 mec2 for 56Fe, 56Co, 56Ni, 56Mn, 56Cr and 56V respectively at ρ7 = 10.7, Ye = 0.45 and T9 = 15. Furthermore, the influence on NES due to EC for different nuclei has some otherness because of different Q0-values. For example, the spectrum of 56Co shows a double bump structure.

Keywords physical data and processes: neutrinos, nuclear reactions — stars: supernovae — stars: evolution

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