Convective overshooting and production of s-nuclei in massive stars during their core He-burning phase

Original · EN

With the "post-processing" technique we explore the role of the convective overshooting on the production of s-nuclei in stellar models of different initial mass and metallicity (15 ≤ MZAMS/M ≤ 25; 10⁻⁴ ≤ Z ≤ 0.02), considering a range of values for the parameter f, which determines the overall efficiency of convective overshooting.We find enhancements in the production of s-nuclei until a factor 6 (measured as the average overproduction factor of the 6 s-only nuclear species with 60 A90) in all our models of different initial mass and metallicity with f in the range 0.01-0.035 (i.e. models with overshooting) compared to the production obtained with "no-overshooting" models (i.e. models with the same initial mass and metallicity, but f=10⁻⁵). Moreover the results indicate that the link between the overshooting parameter f and the s-process efficiency is essentially monotonic in all our models of different initial mass and metallicity. Also evident is the higher s-process efficiency when we progressively increase for a given f value both the mass of the models from 15 M to 25 M and the Z value from 10⁻⁴ to 0.02. We also briefly discuss the possible consequences of these results for some open questions linked to the s-process weak component efficiency, as well as a "rule of thumb" to evaluate the impact of the convective overshooting on the yields of a generation of stars.