21Na(p,γ)22Mgthermonuclear rate for22Naproduction in novae

Classical novae are potential sources of $\gamma$ rays, like the 1.275 MeV gamma emission following ${}^{22}\mathrm{Na}$ beta decay, that could be detected by appropriate instruments on board of future satellites like INTEGRAL. It has been shown that the production of ${}^{22}\mathrm{Na}$ by novae is affected by the uncertainty on the ${}^{21}\mathrm{Na}(p,\gamma {)}^{22}\mathrm{Mg}$ rate and in particular by the unknown partial widths of the $E_x=5.714,$ $J^{\pi }{=2\mathrm{}}^{+},$ ${}^{22}\mathrm{Mg}$ level. To reduce these uncertainties, we performed shell model calculations with the OXBASH code, compared the results with available spectroscopic data, and calculated the missing partial widths. Finally, we discuss the influence of these results on the ${}^{21}\mathrm{Na}(p,\gamma {)}^{22}\mathrm{Mg}$ reaction rate and ${}^{22}\mathrm{Na}$ synthesis.