New limits for the F-18(p,alpha)O-15 rate in Novae

Abstract

The degree to which the (p, gamma) and (p, alpha) reactions destroy F-18 at temperatures similar to 14x10(8) K is important for understanding the synthesis of nuclei in nova explosions and for using the long-lived radionuclide F-18, a target of gamma ray astronomy, as a diagnostic of nova mechanisms. The reactions are dominated by low-lying proton resonances near the F-18+p threshold (E-x=6.411 MeV in Ne-19). To gain further information about these resonances, we have used the d (F-18,p)F-19 neutron transfer reaction to selectively populate corresponding mirror states in F-19. The results would suggest F-18(p, gamma)Ne-19 and F-18(p, alpha)O-15 reaction rates that are 2-3 times lower than reported previously.