Stellar electron capture rates on neutron-rich nuclei and their impact on core-collapse

Abstract

During the late stages of gravitational core-collapse of massive stars, extreme isospin asymmetries are reached within the core. Due to the lack of microscopic calculations of electron capture (EC) rates for all relevant nuclei, in general simple analytic parameterizations are employed. We study here several extensions of these parameterizations, allowing for a temperature, electron density and isospin dependence as well as for odd-even effects. The latter extra degrees of freedom considerably improve the agreement with large scale microscopic rate calculations. We find, in particular, that the isospin dependence leads to a significant reduction of the global EC rates during core collapse with respect to fiducial results, where rates optimized on calculations of stable $fp$-shell nuclei are used. Our results indicate that systematic microscopic calculations and experimental measurements in the $N\approx 50$ neutron rich region are desirable for realistic simulations of the core-collapse.

14 pages, 8 figures, accepted for publication in Phys. Rev. C

References in corpus (4)

• Theory of Core-Collapse Supernovae
• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Stellar electron-capture rates calculated with the finite-temperature relativistic random-phase approximation
• Nuclear weak interaction rates in primordial nucleosynthesis

Cited by in corpus (9)

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• Nuclei in Core-Collapse Supernovae Engine
• Finite-temperature electron-capture rates for neutron-rich nuclei around N=50 and effects on core-collapse supernovae simulations
• General-relativistic radiation transport scheme in Gmunu II: Implementation of novel microphysical library for neutrino radiation -- Weakhub
• Nuclear Shell Structure in a Finite-Temperature Relativistic Framework
• Neutrino Spectra from Nuclear Weak Interactions in $sd$-Shell Nuclei Under Astrophysical Conditions
• Comparison of Electron Capture Rates in the N=50 Region using 1D Simulations of Core-collapse Supernovae