Related papers: Neutron-Capture Element Trends in the Halo
The chemical abundances of metal-poor stars provide important clues to explore stellar formation history and set significant constraints on models of the r-process. In this work, we find that the abundance patterns of the light and iron…
We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detected previously in halo stars, and the elements tellurium,…
In this short paper, we argue the issue on dark matter capture in neutron stars. After summarizing the whole scenario and the introduction of previous studies along this line, we propose some potentially important effects due to the…
We present the science case for characterizing the origin of the heaviest elements on the periodic table, with a focus on those produced by the rapid neutron-capture process (r-process), using the Habitable Worlds Observatory (HWO).…
An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of ~10^-3 times the solar value. Another…
Halo globular clusters pose four succinct issues that must be solved in any scenario of their formation: single-age, single metallicity stellar populations; a lower limit ([Fe/H] ~ -2.3) to their average metallicity; comprising only 1% of…
Heavy element abundances in extremely metal-poor stars provide strong constraints on the processes of forming these elements in the first stars. We attempt to determine precise abundances of strontium in a homogeneous sample of extremely…
We identified 8 additional stars as members of the Helmi stream (HStr) in the combined GALAH+ DR3 and $Gaia$ EDR3 catalog. By consistently reevaluating claimed members from the literature, we consolidate a sample of 22 HStr stars with…
The aim of this work is to determine abundances of neutron-capture elements for thin- and thick-disc F, G, and K stars in several sky fields near the north ecliptic pole and to compare the results with the Galactic chemical evolution…
We investigate the enrichment of europium, as a representative of r-process elements, in the Galactic halo. In present chemical evolution models, stars are assumed to be formed through shock processes by supernovae (SNe). The enrichment of…
Analysis of HST STIS ultraviolet spectra of two hot extreme helium stars (EHes): V1920 Cyg and HD 124448 provide the first measurements of abundances of neutron-capture elements for EHes. Although the two stars have similar abundances for…
The discovery of gravitational waves has confirmed old theoretical predictions that binary systems formed with compact stars play a crucial role not only for cosmology and nuclear astrophysics. As a byproduct of these and subsequent…
We have derived new abundances of the rare-earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good…
Neutron stars capture dark matter efficiently. The kinetic energy transferred during capture heats old neutron stars in the local galactic halo to temperatures detectable by upcoming infrared telescopes. We derive the sensitivity of this…
The abundances of r-process elements of very metal-poor stars capture the history of the r-process enrichment in the early stage of star formation in a galaxy. Currently, various types of astrophysical sites including neutron star mergers,…
Barium stars show enhanced abundances of the slow neutron capture (s-process) heavy elements, and for this reason they are suitable objects for the study of s-process elements. The aim of this work is to quantify the contributions of the…
Various nucleosynthesis studies have pointed out that the r-process elements in very metal-poor (VMP) halo stars might have different origins. By means of familiar concepts from statistics (correlations, cluster analysis, rank tests of…
We present high-resolution of spectroscopy of four stars in two candidate ultra-faint dwarf galaxies (UFDs) Grus I (Gru I) and Triangulum II (Tri II). Neither object currently has a clearly determined velocity dispersion, placing them in an…
Studying the abundances in metal-poor globular clusters is crucial for understanding the formation of the Galaxy and the nucleosynthesis processes in the early Universe. We observed 13 red giant stars from the metal-poor globular cluster…
High resolution (R > 40 000) and high S/N spectra have been acquired with UVES on the VLT-Kueyen (Paranal Observatory, ESO Chile) for several main sequence turnoff stars (V ~ 17 mag) and subgiants at the base of the Red Giant Branch (V ~ 16…