The 17O(p,α) 14Nand 17O(p,γ ) 18F reactions are of paramount importance for the nucleosynthesis in a number of stellar sites, including red giants (RGs), asymptotic giant branch (AGB) stars, massive stars, and classical novae. In particular, they govern the destruction of 17O and the formation of the short-lived radioisotope 18F, which is of special interest for γ -ray astronomy. At temperatures typical of the above-mentioned astrophysical scenario, T = 0.01–0.1 GK for RG, AGB, and massive stars and T = 0.1–0.4 GK for a classical nova explosion, the 17O(p,α) 14Nreaction cross section is dominated by two resonances: one at aboutEcm R = 65 keVabove the 18F proton threshold energy, corresponding to the EX = 5.673 MeV level in 18F, and another one at Ecm R = 183 keV (EX = 5.786 MeV).We report on the indirect study of the 17O(p,α) 14N reaction via the Trojan Horse method by applying the approach recently developed for extracting the strength of narrowresonance at ultralowenergies. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature. This value was used as input parameter for reaction-rate determination and its comparison with the result of the direct measurement is also discussed in the light of the electron screening effect.

Improvement of the high-accuracy 17O( p,α)14N reaction-rate measurement via the Trojan Horse method for application to 17O nucleosynthesis

M. L. Sergi
Primo
;
Lamia L;G. G. Rapisarda;
2015

Abstract

The 17O(p,α) 14Nand 17O(p,γ ) 18F reactions are of paramount importance for the nucleosynthesis in a number of stellar sites, including red giants (RGs), asymptotic giant branch (AGB) stars, massive stars, and classical novae. In particular, they govern the destruction of 17O and the formation of the short-lived radioisotope 18F, which is of special interest for γ -ray astronomy. At temperatures typical of the above-mentioned astrophysical scenario, T = 0.01–0.1 GK for RG, AGB, and massive stars and T = 0.1–0.4 GK for a classical nova explosion, the 17O(p,α) 14Nreaction cross section is dominated by two resonances: one at aboutEcm R = 65 keVabove the 18F proton threshold energy, corresponding to the EX = 5.673 MeV level in 18F, and another one at Ecm R = 183 keV (EX = 5.786 MeV).We report on the indirect study of the 17O(p,α) 14N reaction via the Trojan Horse method by applying the approach recently developed for extracting the strength of narrowresonance at ultralowenergies. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature. This value was used as input parameter for reaction-rate determination and its comparison with the result of the direct measurement is also discussed in the light of the electron screening effect.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/241262
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