Reevaluation of the ${}^{22}$Na(p,$\gamma$) reaction rate: Implications for the detection of ${}^{22}$Na gamma rays from novae

Abstract

Understanding the processes which create and destroy ${}^{22}$Na is important for diagnosing classical nova outbursts. Conventional ${}^{22}$Na(p,$\gamma$) studies are complicated by the need to employ radioactive targets. In contrast, we have formed the particle-unbound states of interest through the heavy-ion fusion reaction, ${}^{12}$C(${}^{12}$C,n)${}^{23}$Mg and used the Gammasphere array to investigate their radiative decay branches. Detailed spectroscopy was possible and the ${}^{22}$Na(p,$\gamma$) reaction rate has been re-evaluated. New hydrodynamical calculations incorporating the upper and lower limits on the new rate suggest a reduction in the yield of ${}^{22}$Na with respect to previous estimates, implying a reduction in the maximum detectability distance for ${}^{22}$Na $\gamma$ rays from novae.

4 pages, 1 figure