Modification of magicity towards the dripline and its impact on electron-capture rates for stellar core-collapse

Abstract

The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of the core collapse dynamics, and the subsequent supernova explosion, is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron rich nuclei on the matter composition during collapse, and the corresponding electron capture rate. To this aim, we introduce an empirical modification of the popular Duflo-Zuker mass model to account for possible shell quenching far from stability, and study the effect of the quenching on the average electron capture rate. We show that the preeminence of the $N=50$ and $N=82$ closed shells in the collapse dynamics is considerably decreased if the shell gaps are reduced in the region of ${}^{78}$Ni and beyond. As a consequence, local modifications of the overall electron capture rate up to 30\% can be expected, with integrated values strongly dependent on the stiffness of magicity quenching and progenitor mass and potential important consequences on the entropy generation, the neutrino emissivity, and the mass of the core at bounce. Our work underlines the importance of new experimental measurements in this region of the nuclear chart, the most crucial information being the nuclear mass and the Gamow-Teller strength. Reliable microscopic calculations of the associated elementary rate, in a wide range of temperatures and electron densities, optimized on these new empirical information, will be additionally needed to get quantitative predictions of the collapse dynamics.

12 pages, 10 figures

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Cited by in corpus (16)

• Equations of state for supernovae and compact stars
• Neutron Stars and the Nuclear Equation of State
• Astronuclear Physics: a Tale of the Atomic Nuclei in the Skies
• Nuclear Equation of state for Compact Stars and Supernovae
• Electron capture in stars
• Supernova equations of state including full nuclear ensemble with in-medium effects
• EoS for hot neutron stars
• Neutrino emissions in all flavors up to the pre-bounce of massive stars and the possibility of their detections
• Nuclear Statistical Equilibrium Equation of State for Core Collapse
• Dependence of weak interaction rates on the nuclear composition during stellar core collapse
• Unblocking of stellar electron capture for neutron-rich $N=50$ nuclei at finite temperature
• Stellar electron capture rates on neutron-rich nuclei and their impact on core-collapse
• Impact of electron capture rates on nuclei far from stability on core-collapse supernovae
• Self consistent calculation of the nuclear composition in hot and dense stellar matter
• Sensitivity of nuclear statistical equilibrium to nuclear uncertainties during stellar core collapse
• Equilibrium nuclear ensembles taking into account vaporization of hot nuclei in dense stellar matter