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Hydrogen burning of oxygen-17

Posted on:2011-01-02Degree:Ph.DType:Thesis
University:The University of North Carolina at Chapel HillCandidate:Newton, JosephFull Text:PDF
GTID:2441390002963919Subject:Physics
Abstract/Summary:
Classical novae are explosive binary systems involving the accretion of hydrogen rich material from a main sequence star onto the surface of a white dwarf partner, reaching peak temperatures of T = 0.1-0.4 GK. Observed elemental abundances from the ejecta provide much needed constraints for the modeling of these explosions. Novae are thought to be the most significant source of 15N and 17O in the universe. The 17O(p,gamma)18F and 17O(p,alpha) 14N reactions have an important effect on nucleosynthesis in novae, since they determine the creation and destruction of 17O and 18F, which produces detectable gamma-radiation. The dominant contributor to the 17O(p,alpha)14N reaction is a resonance at Elabr = 193 keV. The strength of this resonance has been measured and the results are presented. For the 17O(p,gamma) 18F reaction, the dominant contribution comes from the nonresonant direct capture process. The literature direct capture cross sections currently differ by a factor of two. This cross section has been measured in the current work and the results are also presented. New reaction rates have been calculated with these measured cross sections using a new Monte Carlo technique and these new rates have significantly reduced uncertainties compared to the current literature.
Keywords/Search Tags:17O
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