Gamma Ray Heating and Neutrino Cooling Rates due to Weak Interaction Processes on sd-shell Nuclei in Stellar Cores

Abstract

Gamma ray heating and neutrino cooling rates, due to weak interaction processes, on $sd$-shell nuclei in stellar core are calculated using the proton neutron quasiparticle random phase approximation theory. The recent extensive experimental mass compilation of \citep{Wang12}, other improved model input parameters including nuclear quadrupole deformation \citep{Ram01}, \citep{Mol16} and physical constants are taken into account in the current calculation. The purpose of this work is two fold, one is to improve the earlier calculation of weak rates performed by \citep{Nabi99} using the same theory. We further compare our results with previous calculations. The selected $sd$-shell nuclei, considered in this work, are of special interest for the evolution of O-Ne-Mg core in 8-10 M${}_{\odot }$ stars due to competitive gamma ray heating rates and cooling by URCA processes. The outcome of these competitions is to determine, whether the stars end up as a white dwarf \citep{Nabi08}, an electron-capture supernova \citep{Jones13} or Fe core-collapse supernova \citep{Suz16}. The selected $sd$-shell nuclei for calculation of associated weak-interaction rates include ${}^{20,23}$O, ${}^{20,23}$F, ${}^{20,23,24}$Ne, ${}^{20,23-25}$Na, and ${}^{23-25}$Mg. The cooling and heating rates are calculated for density range ($10\le \rho ($\;g.cm${}^{-3})\le$ 10${}^{11}$) and temperature range ($0.01\times 10^9$ $\le$ $T(K)$ $\le$ $30\times 10^9$). The calculated gamma heating rates are orders of magnitude bigger than the shell model rates (except for ${}^{25}$Mg at low densities). At high temperatures the gamma heating rates are in reasonable agreement. The calculated cooling rates are up to an order of magnitude bigger for odd-A nuclei.

arXiv comment25 Pages, 13 Tables, 6 Figures

References in corpus (13)

• Nuclear ground-state masses and deformations: FRDM(2012)
• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Heating in the Accreted Neutron Star Ocean: Implications for Superburst Ignition
• Advanced burning stages and fate of 8-10 Mo stars
• Weak Interaction Rates Of sd-Shell Nuclei In Stellar Environment Calculated in the Proton-Neutron Quasiparticle Random Phase Approximation
• Electron capture and beta-decay rates for sd-shell nuclei in stellar environments relevant to high density O-Ne-Mg cores
• Astrophysical weak-interaction rates for selected $A=20$ and $A=24$ nuclei
• Microscopic Calculations of Weak Interaction Rates of Nuclei in Stellar Environment for A = 18 to 100
• The gravitational collapse of ONe electron-degenerate cores and white dwarfs: the role of ${}^{24}$Mg and ${}^{12}$C revisited
• Gamow-Teller transitions from 24Mg and its impact on the electron capture rates in the O + Ne + Mg cores of stars
• Stellar neutrino energy loss rates due to ${}^{24}$Mg suitable for O+Ne+Mg core simulations
• Nuclear structure and weak rates of heavy waiting point nuclei under rp-process conditions
• Effect of ${}^{12}C+$ ${}^{12}C$ Reaction & Convective Mixing on the Progenitor Mass of ONe White Dwarfs