Related papers: Decoding the compositions of four bright $r$-proce…
Understanding the origin of the elements has been a decades long pursuit, with many open questions still remaining. Old stars found in the Milky Way and its dwarf satellite galaxies can provide answers because they preserve clean elemental…
New measurements of neutron-capture elements are presented for two very metal-poor stars ([Fe/H] ~ -3). One (LP 625-44) has an s-process signature believed to be due to mass transfer from a now-extinct metal-poor AGB companion, and the…
Based on the high resolution and high signal-to-noise spectra, we derived the chemical abundances of 20 elements for 20 barium (Ba-) stars. For the first time, the detailed abundances of four sample stars, namely HD 92482, HD 150430, HD…
(Abridged) The stellar sites and the complete mechanism of r-process nucleosynthesis are still unresolved issues. From consideration of the observed abundances in metal-poor stars, it is proposed that the production of the heavy r-process…
We present analysis of high-resolution spectra of a sample of stars in the globular cluster M5 (NGC 5904). The sample includes stars from the red giant branch (seven stars), the red horizontal branch (two stars), and the asymptotic giant…
I show that recent observations of r-process abundances in metal-poor stars are difficult to explain if neutron star mergers (NSMs) are the major r-process sources. In contrast, such observations and meteoritic data on Hf182 and I129 in the…
We propose a new neutron-capture site in early metal-poor and metal-free stars of $\sim 20$--$30 \,\mathrm{M}_\odot$ that results from proton ingestion in the He shell during late stages of the stars' lives. Most of the neutron capture…
The detailed chemical composition of most metal-poor halo stars has been found to be highly uniform, but a minority of stars exhibit dramatic enhancements in their abundances of heavy neutron-capture elements and/or of carbon. The key…
A long-standing scientific puzzle has been to explain the origin of the heaviest elements in the Universe and, more particularly, the production of the elements heavier than iron up to uranium. The rapid neutron capture process (or…
Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Z<~50 while the other…
The stellar record of elemental abundances in satellite galaxies is important to identify the origin of r-process because such a small stellar system could have hosted a single r-process event, which would distinguish member stars that are…
Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…
High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely metal-poor giant with large relative enhancements…
We present abundances of Mn, Cu, Zn and various light and heavy elements for a sample of barium and normal giant stars, and present correlations between abundances contributed to different degrees by the weak-s, main-s, and r-processes of…
Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier transform…
The atmospheres of phosphorus-rich stars have been shown to contain between 10 and 100 times more P than our Sun. Given its crucial role as an essential element for life, it is especially necessary to uncover the origin of P-rich stars to…
In this study, abundances of the neutron-capture elements Rb, Sr, and Zr are derived, for the first time, in a sample of nearby M dwarfs. We focus on stars in the metallicity range -0.5<[Fe/H]<+0.3, an interval poorly explored for Rb…
A few rare halo giants in the range [Fe/H] $\simeq -2.9\pm0.3$ exhibit {\it r}-process element abundances that vary as a group by factors up to [$r$/Fe] $\sim80$, relative to those of the iron peak and below. Yet, the astrophysical…
Growing interests in the chemical feature of r-process elements among nearby disk stars represented by the [Eu/Fe] vs. [Fe/H] diagram have sprouted since it can assess the origin of r-process elements through the comparison with theoretical…
The properties of the relative abundances of rapid and slow neutron-capture elements are studied using a catalog containing spectroscopic abundance determinations for 14~elements produced in various nuclear-synthesis processes for 90~open…