Related papers: The s Process: Nuclear Physics, Stellar Models, Ob…
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…
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…
Low-mass stars are element factories that efficiently release their products in the final stages of their evolution by means of stellar winds. Since they are large in number, they contribute significantly to the cosmic matter cycle. To…
In a diagram of metallicity (\~z) vs. luminosity (M$_B$), the different types of nearby (Z $< 0.05$) starburst galaxies seem to follow the same linear relationship as the normal spiral and irregular galaxies. However, for comparable…
We compute chemical evolution models to constrain the mode and the history of star formation in starburst galaxies as a whole, i.e. over a large range of mass and metallicity. To this end, we investigate the origin of the dispersion…
Energy in stars is provided by nuclear reactions, which, in many cases, produce radioactive nuclei. When stable nuclei are irradiated by a flux of protons or neutrons, capture reactions push stable matter out of stability into the regime of…
Extremely metal-poor low-mass stars experience an ingestion of protons into the helium-rich layer during the core He-flash, resulting in the production of neutrons through the reactions ^{12}C(p,\gamma)^{13}N(\beta)^{13}C(\alpha,n)^{16}O.…
Carbon-enhanced metal-poor (CEMP) stars in the Galactic Halo display enrichments in heavy elements associated with either the s (slow) or the r (rapid) neutron-capture process (e.g., barium and europium respectively), and in some cases they…
FUSE spectroscopy has proved that extremely hot hydrogen-deficient post-AGB stars (PG1159 stars) display matter on their surface that usually remains hidden in the region between the H- and He-burning shells of the former AGB star. Hence,…
Knowledge of abundance ratios as functions of metallicity can lead to insights on the origin and evolution of our Galaxy and its stellar populations. We aim to trace the chemical evolution of the neutron-capture elements Sr, Zr, La, Ce, Nd,…
Carbon (C) is thought to be produced by both core collapse supernovae (CCSN) and asymptotic giant branch (AGB) stars, but the relative contributions of these two sources are uncertain. We investigate the astrophysical origin of C using…
Nuclear masses play a fundamental role in understanding how the heaviest elements in the Universe are created in the $r$-process. We predict $r$-process nucleosynthesis yields using neutron capture and photodissociation rates that are based…
Some metal-poor stars have abundance patterns which are midway between the slow (s) and rapid (r) neutron capture processes. We show that the helium shell of a fast rotating massive star experiencing a jet-like explosion undergoes two…
Nuclear physics has a long and productive history of application to astrophysics which continues today. Advances in the accuracy and breadth of astrophysical data and theory drive the need for better experimental and theoretical…
Bulk meteoritic data show isotopic variability of $slow$-neutron-capture ($s$-process) origin in a several elements heavier than Fe. One peculiar feature is that the lighter $s$-process elements (e.g., Zr and Mo) present larger anomalies…
It has been shown that proton ingestion episodes can happen in the formation of hot-subdwarf stars, and that neutron-capture processes are possible in those cases. Moreover, some helium-rich hot subdwarfs display extraordinarily high…
The enrichment of Pb in the Galaxy is followed in the framework of a detailed model of Galactic chemical evolution that already proved adequate to reproduce the chemical enrichment of O and of the elements from Ba to Eu. The stellar yields…
(abridged) We model the nucleosynthesis during the thermal pulse phase of a rotating, solar metallicity AGB star of 3M_sun. Rotationally induced mixing during the thermal pulses produces a layer (~2E-5M_sun) on top of the CO-core where…
Barium stars are s-process enriched giants. They owe their chemical peculiarities to a past mass transfer phase. During which they were polluted by their binary companion, which at the time was an AGB star, but is now an extinct white…
We revisit a neutrino-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity < solar/1000, at relatively low temperatures and neutron densities, producing A ~ 130…