Ne(p,γ)Na and Ne(d,n)Na reactions and its astrophysical implications for the transition of the hot CNO cycle to the rp process

The population of the Na resonances at 448, 661, 797, and 887 keV above the proton threshold has been studied in measurements of the Ne(p, γ)Na reaction with radioactive Ne beams. The data have been analyzed fully in terms of resonance strengths, enabling a comparison with theoretical estimates and the extraction of upper and lower limits on the resonant part of the Ne(p, γ)Na astrophysical reaction rate. The total cross section of the Ne(d,n)Na reaction has been measured from 0.6 to 1.8 MeV (c.m.). On the basis of the results of a subsequent distorted-wave Born approximation analysis the direct component of the Ne(p, γ)Na astrophysical reaction rate has been calculated in a potential model. The astrophysical implications of the resulting total reaction rate have been investigated: the conditions for the breakout from the hot CNO cycle into the rapid-proton capture process are determined by the preceding O(α, γ)Ne reaction and the photodisintegration of the produced Na nuclei will not impede the breakout.