Alpha-decay branching ratios of near-threshold states in 19Ne and the astrophysical rate of 15O(alpha,gamma)19Ne

Abstract

The 15O(alpha,gamma)19Ne reaction is one of two routes for breakout from the hot CNO cycles into the rp process in accreting neutron stars. Its astrophysical rate depends critically on the decay properties of excited states in 19Ne lying just above the 15O + alpha threshold. We have measured the alpha-decay branching ratios for these states using the p(21Ne,t)19Ne reaction at 43 MeV/u. Combining our measurements with previous determinations of the radiative widths of these states, we conclude that no significant breakout from the hot CNO cycle into the rp process in novae is possible via 15O(alpha,gamma)19Ne, assuming current models accurately represent their temperature and density conditions.

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Cited by in corpus (6)

• X-ray binaries
• The astrophysical rate of 15O(alpha,gamma)19Ne via the (p,t) reaction in inverse kinematics
• Particle decay branching ratios for states of astrophysical importance in 19Ne
• The Influence of Uncertainties in the 15O(alpha,gamma)19Ne Reaction Rate on Models of Type I X-Ray Bursts
• Proton-decaying states in 22Mg and the nucleosynthesis of 22Na in novae
• The 2025 Evaluation of Experimental Thermonuclear Reaction Rates (ETR25)