Related papers: s-Process Nucleosynthesis in Carbon Stars
Asymptotic Giant Branch (AGB) stars play a key role in the chemical evolution of galaxies. These stars are the fundamental stellar site for the production of light elements such as C, N and F, and half of the elements heavier than Fe via…
The s-process in AGB stars produces elements with atomic mass numbers $A\gtrsim60$ through successive neutron captures and beta decays. In stellar environments where the s-process occurs, neutrons quickly thermalize, adopting a…
Context- S stars are late-type giants with spectra showing characteristic molecular bands of ZrO in addition to the TiO bands typical of M stars. Their overabundance pattern shows the signature of s-process nucleosynthesis. Intrinsic,…
In this paper we present a large-scale sensitivity study of reaction rates in the main component of the $s$ process. The aim of this study is to identify all rates, which have a global effect on the $s$ process abundance distribution and…
We present the abundance analyses of 7 Carbon enhanced metal-poor (CEMP) stars to understand the origin of carbon in them. We used high-resolution optical spectra to derive abundances of various elements. We also used low-resolution…
We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the…
The metal-free (Pop. III) and extremely metal-poor (EMP) stars of low- and intermediate-masses experience mixing of hydrogen into the helium convection during the early TP-AGB phase, differently from the meal-rich stars. We study the…
About half of the mass of all heavy elements with mass number A > 90 is formed through the slow neutron capture process (s-process), occurring in evolved asymptotic giant branch (AGB) stars with masses ~1-6 $\rm{M_{\odot}}$. The s-process…
Abundances of low-metallicity stars offer a unique opportunity to understand the contribution and conditions of the different processes that synthesize heavy elements. Many old, metal-poor stars show a robust abundance pattern for elements…
Asymptotic Giant Branch (AGB) stars play a fundamental role in the s-process nucleosynthesis during their thermal pulsing phase. The theoretical predictions obtained by AGB models at different masses, s-process efficiencies, dilution…
We present a detailed study of s-process nucleosynthesis in massive stars of solar-like initial composition and masses 15, 20,25, and 30 Msun. We update our previous results of s-process nucleosynthesis during the core He-burning of these…
Aims. We investigate the s-process during the AGB phase of stellar models whose cores are enforced to rotate at rates consistent with asteroseismology observations of their progenitors and successors. Methods. We calculated new…
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…
The chemical compositions of evolved stars in Local Group dwarf spheroidal galaxies (dSphs) provide insight into the galaxy's past star formation and nucleosynthesis. Neutron-capture element abundances are especially interesting. In…
The concomitant overabundances of C, N and s-process elements are commonly ascribed to the complex interplay of nucleosynthesis, mixing and mass loss taking place in Asymptotic Giant Branch stars. At low metallicity, the enhancement of C…
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…
We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and…
High dispersion near-infrared spectra have been taken of seven highly-evolved, variable, intermediate-mass (4-6 Msun) AGB stars in the LMC and SMC in order to look for C, N and O variations that are expected to arise from third dredge-up…
Several stars at the low-metallicity extreme of the Galactic halo ([Fe/H]=-2.5) show strong enhancements of both s-process and r-process elements. The presence of s-process elements in main-sequence stars is explained via mass transfer from…
We analyze the chemical composition of the planetary nebula (PN) NGC 5315, through high-resolution (R = 40000) optical spectroscopy with UVES at the Very Large Telescope, and medium-resolution (R = 4800) near-infrared spectroscopy with FIRE…