19Ne(p,γ)20Na and 19Ne(d,n)20Na reactions and its astrophysical implications for the transition of the hot CNO cycle to the rp process

The population of the 20Na resonances at 448, 661, 797, and 887 keV above the proton threshold has been studied in measurements of the 19Ne(p, γ)20Na reaction with radioactive 19Ne 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 19Ne(p, γ)20Na astrophysical reaction rate. The total cross section of the 19Ne(d,n)20Na 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 19Ne(p, γ)20Na 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 15O(α, γ)19Ne reaction and the photodisintegration of the produced 20Na nuclei will not impede the breakout.SCOPUS: ar.j