Astrophysical implications of the proton-proton cross section updates

الأصل · EN

The p(p,e+ νₑ)²H reaction rate is an essential ingredient for theoretical computations of stellar models. In the past several values of the corresponding S-factor have been made available by different authors. Prompted by a recent evaluation of S(E), we analysed the effect of the adoption of different proton-proton reaction rates on stellar models, focusing, in particular, on the age of mid and old stellar clusters (1-12 Gyr) and on standard solar model predictions. By comparing different widely adopted p(p,e+ νₑ)²H reaction rates, we found a maximum difference in the temperature regimes typical of main sequence hydrogen-burning stars (5x10⁶ - 3x10⁷ K) of about 3%. Such a variation translates into a change of cluster age determination lower than 1%. A slightly larger effect is observed in the predicted solar neutrino fluxes with a maximum difference, in the worst case, of about 8%. Finally we also notice that the uncertainty evaluation of the present proton-proton rate is at the level of few, thus the p(p,e+ νₑ)²H reaction rate does not constitute anymore a significant uncertainty source in stellar models.