ReactionNa23(α,p)Mg26fromEα=2.3−3.7MeV and the corresponding thermonuclear reaction rate

Abstract

Integrated excitation functions for the reactions $^{23}\mathrm{Na}(\ensuremath{\alpha},{p}_{0})^{26}\mathrm{Mg}$ and $^{23}\mathrm{Na}(\ensuremath{\alpha},{p}_{1})^{26}\mathrm{Mg}^{*}$ were measured over the energy range ${E}_{\ensuremath{\alpha}}=2.3\ensuremath{-}3.7$ MeV. Absolute resonance strengths were determined for 30 new ${p}_{1}$ resonances and 9 new ${p}_{0}$ resonances. The corresponding stellar reaction rate ${N}_{A}<\ensuremath{\sigma}V>$ is recalculated and found to be enhanced by a factor of 3 at ${T}_{9}=2$ and by a factor of 4 at ${T}_{9}=3$. A multiparameter analytic fit to the new ${N}_{A}<\ensuremath{\sigma}V>$ as a function of temperature over the range ${T}_{9}=0.3\ensuremath{-}5.0$ is given. The enhanced rate was incorporated in a nucleosynthesis code and the resulting change in $^{23}\mathrm{Na}$ and $^{26}\mathrm{Mg}$ abundances at selected temperatures is discussed.[NUCLEAR REACTIONS $^{23}\mathrm{Na}(\ensuremath{\alpha},p)$, $E=2.3\ensuremath{-}3.7$ MeV; measured excitation function and deduced resonant strengths for ${p}_{0}$ and ${p}_{1}$ proton groups; NaCl target. Calculated new thermonuclear reaction rate.]