Related papers: r-Process Enhanced Halo Stars
It is argued that the abundances of r-process related elements in stars with -3<[Fe/H]<-1 can be explained by the contributions of three sources. The sources are: the first generations of very massive (>100 solar masses) stars that are…
Nucleocosmochronology involves the use of the abundances of radioactive nuclear species and their radiogenic decay daughters to establish the finite age of the elements and the time scale for their formation. While there exist radioactive…
About half of the heavy elements in the Solar System were created by rapid neutron capture, or r-process, nucleosynthesis. In the r-process, heavy elements are built up via a sequence of neutron captures and beta decays in which an intense…
The differences between the neutron-capture element abundances of halo stars are important to our understanding of the nucleosynthesis of elements heavier than the iron group. We present a detailed abundance analysis of carbon and twelve…
We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy…
We report on a detailed abundance analysis of the r-process enhanced giant star, HE 2252-4225 ([Fe/H] = -2.63, [r/Fe] = 0.80). Determination of stellar parameters and element abundances was based on analysis of high-quality VLT/UVES…
The ultra-faint dwarf galaxy Reticulum II was enriched by a rare and prolific r-process event, such as a neutron star merger. To investigate the nature of this event, we present high-resolution Magellan/MIKE spectroscopy of the brightest…
The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and…
The r-process involves neutron-rich nuclei far off stability for which no experimental cross sections are known. Therefore, one has to rely on theory. The difficulties in the predictions are briefly addressed. To investigate the impact of…
The supernova yields of several heavy elements including alpha-, iron-group, and r-process elements are obtained as a function of the mass of their progenitor main-sequence stars M_ms from the abundance patterns of extremely metal-poor…
Several works have found an increase of the abundances of the s-process neutron-capture elements in the youngest Galactic stellar populations, giving important constraints to stellar and Galactic evolution. We aim to trace the abundance…
Some of the heavy elements, such as gold and europium (Eu), are almost exclusively formed by the rapid neutron capture process (r-process). However, it is still unclear which astrophysical site between core-collapse supernovae and neutron…
The abundance of elements synthesized by the rapid neutron-capture process (r-process elements) of extremely metal-poor (EMP) stars in the Local Group galaxies gives us clues to clarify the early evolutionary history of the Milky Way halo.…
Binary mergers (NSMs) of double neutron star (and black hole-neutron star) systems are suggested to be major sites of r-process elements in the Galaxy by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however,…
We study the evolution of Eu and Ba abundances in local group dwarf spheroidal and ultra faint dwarf galaxies by means of detailed chemical evolution models and compare our results with new sets of homogeneous abundances. The adopted models…
The rapid neutron capture process (r-process) is thought to be responsible for the creation of more than half of all elements beyond iron. The scientific challenges to understanding the origin of the heavy elements beyond iron lie in both…
The early-R stars are carbon-rich K-type giants. They are enhanced in C12, C13 and N14, have approximately solar oxygen, magnesium isotopes, s-process and iron abundances, have the luminosity of core-helium burning stars, are not rapid…
The exact evolution of elements in the universe, from primordial to heavier elements produced via the r-process, is still under scrutiny. The supernova deaths of the very first stars led to the enrichment of their local environments, and…
Solar twins, i.e., stars that are nearly identical to the Sun, including their metallicities, in the solar vicinity show ages widely distributed from 0-10 Gyr. This fact matches the orbital history of solar twins in the new paradigm of…
Recent observations of heavy elements in Globular Clusters reveal intriguing deviations from the standard paradigm of the early galactic nucleosynthesis. If the r-process contamination is a common feature of halo stars, s-process…