Related papers: s-Process Nucleosynthesis in AGB Stars: A Test for…
Aims. We present the implementation of the treatment of particle ejection and dust nucleation in the smoothed particle hydrodynamics (SPH) code phantom. These developments represent the first step toward a more complete modeling of…
The evolution on the AGB and beyond is reviewed with respect to the origin of Wolf-Rayet central stars. We focus on thermal pulses due to their particular importance for the evolution of hydrogen deficient stars. It is shown that overshoot…
Lithium and zirconium abundances (the latter taken as representative for s-process enrichment) are determined for a large sample of massive Galactic O-rich AGB stars, for which high resolution optical spectroscopy has been obtained…
Rocky asteroids and planets display nucleosynthetic isotope variations that are attributed to the heterogeneous distribution of stardust from different stellar sources in the solar protoplanetary disk. Here we report new high precision…
By considering the various CEMP subclasses separately, we try to derive, from the specific signatures imprinted on the abundances, parameters (such as metallicity, mass, temperature, and neutron source) characterizing AGB nucleosynthesis…
We present a novel approach to address dust production by low- and intermediate-mass stars. We study the asymptotic giant branch (AGB) phase, during which the formation of dust takes place, from the perspective of post-AGB and planetary…
The slow ($s$) and intermediate ($i$) neutron ($n$) capture processes occur both in asymptotic giant branch (AGB) stars, and in massive stars. To study the build-up of the $s$- and $i$-products at low metallicity, we investigate the…
In an effort to extend the still limited sample of s-process enriched post-AGB stars, high-resolution, high signal-to-noise VLT+UVES spectra of the optical counterparts of the infrared sources IRAS06530-0213 and IRAS08143-4406 were…
The triple alpha process plays an important role in the production of 12C in stars. Its rate is known with an accuracy of about 12%. We examine the corresponding uncertainties introduced in the description of pre-supernova stars, of…
We summarise the evolution and nucleosynthesis in AGB and Super-AGB stars. We then examine the major sources of uncertainty, especially mass-loss.
We have studied the sensitivity of s-process nucleosynthesis in massive stars to +/- 2 sigma variations in the rates of the triple alpha and 12C(a,g)16O reactions. We simulated the evolution of massive stars from H-burning through Fe-core…
CEMP-s stars are very metal-poor stars with enhanced abundances of carbon and s-process elements. They form a significant proportion of the very metal-poor stars in the Galactic halo and are mostly observed in binary systems. This suggests…
The s-process production in massive stars at very low metallicities is expected to be negligible due to the low abundance of the neutron source 22Ne, to primary neutron poisons and decreasing iron seed abundances. However, recent models of…
The solar s-process abundances have been analyzed in the framework of a Galactic Chemical Evolution (GCE) model. The aim of this work is to implement the study by Bisterzo et al. (2014), who investigated the effect of one of the major…
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)…
We present the results of simulations of nucleosynthesis in a core-collapse supernova (CCSN) including the neutrino process. Using the Si layer of $13M_\odot$ zero-metal progenitor as the initial composition, we calculate the…
We have investigated a highly energetic H-ingestion event during shell He burning leading to H-burning luminosities of $\log(L_\mathrm{H}/\mathrm{\Lsun}) \sim 13$ in a $45 \Msun$ Pop III massive stellar model. In order to track the…
The reaction 13C(alpha,n) is considered to be the main source of neutrons for the s-process in AGB stars. At low energies the cross section is dominated by the 1/2+ 6.356 MeV sub-threshold resonance in 17O whose contribution is determined…
Recently, measurements of abundances in extremely metal poor (EMP) stars have brought new constraints on stellar evolution models. In an attempt to explain the origin of the abundances observed, we computed pre--supernova evolution models,…
The recently improved information on the stellar neutron capture cross sections of neutron magic nuclei at N = 82, and in particular for 142^Nd, turned out to represent a sensitive test for models of s-process nucleosynthesis. While these…