Related papers: Reaction rates for the s-process neutron source 22…
[abridged] We study the s-process in AGB stars using three different stellar evolutionary models computed for a 3Msun and solar metallicity star. First we investigate the formation and the efficiency of the main neutron source. We…
Contrary to previous expectations, recent evolutionary models of zero-metallicity stars show that the development of mixing episodes at the beginning of the AGB phase allows low- and intermediate-mass stars to experience thermal pulses. If…
In past decades a lot of progress has been made towards understanding the main s-process component that takes place in thermally pulsing Asymptotic Giant Branch (AGB) stars. During this process about half of the heavy elements, mainly…
The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have…
A long debated issue concerning the nucleosynthesis of neutron-rich elements in Asymptotic Giant Branch (AGB) stars is the identification of the neutron source. We report intermediate-mass (4 to 8 solar masses) AGB stars in our Galaxy that…
Within the framework of the current models for the slow neutron capture (s) process in Asymptotic Giant Branch (AGB) stars we explore the uncertainties introduced by the assumptions made on stellar modeling. On the basis of star models…
In this review, we emphasize the interplay between astrophysical observations, modeling, and nuclear physics laboratory experiments. Several important nuclear cross sections for astrophysics have long been identified e.g.…
The ratio between the rates of the reactions O-17(\alpha,n)Ne-20 and O-17(\alpha,\gamma)Ne-21 determines whether O-16 is an efficient neutron poison for the s process in massive stars, or if most of the neutrons captured by O-16(n,\gamma)…
Roughly half of the heavy elements (atomic mass greater than that of iron) are believed to be synthesized in the late evolutionary stages of stars with masses between 0.8 and 8 solar masses. Deep inside the star, nuclei (mainly iron)…
Slow neutron captures are responsible for the production of about $50\%$ of elements heavier than iron, mainly, occurring during the asymptotic giant branch phase of low-mass stars ($1$ $\lesssim M$/M$_{\odot}$ $\lesssim$ $3$), where the…
Effects of a new triple-{\alpha} reaction rate on the s-process during the evolution of a massive star of 25 M\odot are investigated for the first time. Although the s-process in massive stars has been believed to be established with only…
The 12C(p,{\gamma})13N reaction is the onset process of both the CNO and Hot CNO cycles that drive massive star, Red and Asymptotic Giant Branch star and novae nucleosynthesis. The 12C(p,{\gamma})13N rate affects the final abundances of the…
One of the main neutron sources for the astrophysical s-process is the reaction 13C({\alpha},n)16O, taking place in thermally pulsing Asymptotic Giant Branch stars at temperatures around 90 MK. To model the nucleosynthesis during this…
Thermally pulsating asymptotic giant branch (AGB) stars are the main producers of slow neutron capture (s-) process elements, but there are still large uncertainties associated with the formation of the main neutron source, 13C, and with…
The $^{22}$Ne($\alpha,n$)$^{25}$Mg reaction is an important source of neutrons for the s-process. Due to the difficulty in directly measuring the cross section of this reaction and the competing $^{22}$Ne($\alpha,\gamma$)$^{26}$Mg reaction,…
The origin of fluorine is a longstanding problem in nuclear astrophysics. It is widely recognized that Asymptotic Giant Branch (AGB) stars are among the most important contributors to the Galactic fluorine production. In general, extant…
The 16O(p,gamma)17F reaction rate is revisited with special emphasis on the stellar temperature range of T=60-100 MK important for hot bottom burning in asymptotic giant branch (AGB) stars. We evaluate existing cross section data that were…
The 13C(a, n)16O reaction is the major neutron source in low mass asymptotic giant branch (AGB) stars, where the main and the strong s process components are synthesised. After a third dredge-up (TDU) episode, 13C burns radiatively in a…
Stars with initial masses 7 Msun . MZAMS . 9 Msun reach temperatures high enough to ignite C under degenerate conditions after the end of He-core burning (Garcia-Berro & Iben 1994). These isolated stars are expected to evolve into the…
We test the effect of proton-capture reaction rate uncertainties on the abundances of the Ne, Na, Mg and Al isotopes processed by the NeNa and MgAl chains during hot bottom burning (HBB) in asymptotic giant branch (AGB) stars of…