A New 17F(p,gamma)18Ne Reaction Rate and Its Implications for Nova Nucleosynthesis

Abstract

Proton capture by 17F plays an important role in the synthesis of nuclei in nova explosions. A revised rate for this reaction, based on a measurement of the 1H(17F,p)17F excitation function using a radioactive 17F beam at ORNL's Holifield Radioactive Ion Beam Facility, is used to calculate the nucleosynthesis in nova outbursts on the surfaces of 1.25 and 1.35 solar mass ONeMg white dwarfs and a 1.00 solar mass CO white dwarf. We find that the new 17F(p,gamma)18Ne reaction rate changes the abundances of some nuclides (e.g., 17O) synthesized in the hottest zones of an explosion on a 1.35 solar mass white dwarf by more than a factor of 10,000 compared to calculations using some previous estimates for this reaction rate, and by more than a factor of 3 when the entire exploding envelope is considered. In a 1.25 solar mass white dwarf nova explosion, this new rate changes the abundances of some nuclides synthesized in the hottest zones by more than a factor of 600, and by more than a factor of 2 when the entire exploding envelope is considered. Calculations for the 1.00 solar mass white dwarf nova show that this new rate changes the abundance of 18Ne by 21%, but has negligible effect on all other nuclides. Comparison of model predictions with observations is also discussed.