Search for <sup>22</sup>Na in novae supported by a novel method for measuring femtosecond nuclear lifetimes.

Fougères, Chloé; de Oliveira Santos, François; José, Jordi; Michelagnoli, Caterina; Clément, Emmanuel; Kim, Yung Hee; Lemasson, Antoine; Guimarães, Valdir et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Classical novae are thermonuclear explosions in stellar binary systems, and important sources of <sup>26</sup>Al and <sup>22</sup>Na. While γ rays from the decay of the former radioisotope have been observed throughout the Galaxy, <sup>22</sup>Na remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV γ-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The <sup>22</sup>Na(p, γ)<sup>23</sup>Mg reaction remains the only source of large uncertainty about the amount of <sup>22</sup>Na ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in <sup>23</sup>Mg. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the <sup>23</sup>Mg states, places strong limits on the amount of <sup>22</sup>Na produced in novae and constrains its detectability with future space-borne observatories.