The effect of the recent ¹⁷O(p,α)¹⁴N and ¹⁸O(p,α)¹⁵N fusion cross section measurements in the nucleosynthesis of AGB stars

¹ INFN-Laboratori Nazionali del Sud, Catania, Italy
² Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy

^a e-mail: palmerini@lns.infn.it

Published online: 29 January 2015

Abstract

The Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of the ¹⁷O(p,α)¹⁴N and ¹⁸O(p,α)¹⁵N fusion reactions and to extract the strengths of the resonances that more contribute to the reaction rates at astrophysical energies. Moreover, the strength of the 65 keV resonance in the ¹⁷O(p,α)¹⁴N reaction, measured by means of the THM, has been used to renormalize the corresponding resonance strength in the ¹⁷O + p radiative capture channel. Since, proton-induced fusion reactions on ¹⁷O and ¹⁸O belong to the CNO cycle network for H-burning in stars, the new estimates of the cross sections have been introduced into calculations of Asymptotic giant branch (AGB) star nucleosynthesis to determine their impact on astrophysical environments. Results of nucleosynthesis calculations have been compared with geochemical analysis of ”presolar” grains. These solids form in the cold and dusty envelopes that surround AGB stars and once that have been ejected by stellar winds, come to us as inclusions in meteorites providing invaluable benchmarks and constraints for our knowledge of fusion reactions in astrophysical environments.