Related papers: The r-process in the early Galaxy

Metal-poor stars in the Milky Way (MW) halo display large star-to-star dispersion in their r-process abundance relative to lighter elements. This suggests a chemically diverse and unmixed interstellar medium (ISM) in the early Universe.…

We have determined lead (Pb) abundances for twelve red giants having [Fe/H] between -2.1 and -1.3, and its upper-limits for two lower metallicity objects, as well as the abundances of lanthanum (La) and europium (Eu). The averages of…

The abundance scatter of heavier r-process elements (Z > 56) relative to Fe ([r/Fe]) in metal-poor stars preserves excellent information of the star formation history and provides important insights into the various situations of the…

About half of carbon and s-process enhanced metal-poor stars (CEMP-s) show a high r-process enrichment (CEMP-s/r), incompatible with a pure s-process contribution. CEMP-s stars are of low mass (M < 0.9 Msun) and belong to binary systems.…

We present a strictly line-by-line differential analysis of a moderately $r$-process-enhanced star ($r$-I: HD~107752) with respect to a strongly $r$-process-enhanced star ($r$-II: CS~31082-0001) to investigate the possible common origin of…

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…

We investigate the production sites and the enrichment history of $r$-process elements in the Galaxy, as traced by the [Eu/Fe] ratio, using the high resolution, cosmological zoom-in simulation `Eris'. At $z=0$, Eris represents a close…

We have attributed the elements from Sr through Ag in stars of low metallicities ([Fe/H] < -1.5) to charged-particle reactions (CPR) in neutrino-driven winds, which are associated with neutron star formation in low-mass and normal…

The Galactic Centre (GC) has experienced a high degree of recent star-forming activity, as evidenced by the large number of massive stars currently residing there. The relative abundances of chemical elements in the GC may provide insights…

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 investigate the enrichment in elements produced by the slow neutron-capture process ($s$-process) in the globular clusters M4 (NGC 6121) and M22 (NGC 6656). Stars in M4 have homogeneous abundances of Fe and neutron-capture elements, but…

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…

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…

We study the abundance patterns and the radial gradients of s-process elements (Y, Zr, Ba, La and Ce), r-process elements (Eu) and mixed-process elements (Mo, Nd and Pr) in the Galactic thin disc by means of a detailed two-infall chemical…

Chemical elements in the hot medium permeating early-type galaxies, groups, and clusters make them an excellent laboratory for studying metal enrichment and cycling processes in the largest scales of the universe. Here, we report the…

We analyze data from several studies of metal-poor stars in the Milky Way, focusing on both strong (Eu) and weak (Sr) $r$-process elements. Because these elements were injected in an explosion, we calculate the mass swept up when the blast…

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…

We examine the r-process in the neutrino-driven proto-neutron-star (PNS) wind of core-collapse supernovae in light of the recent findings of massive neutron stars in binaries as well as of an indication of neutron-richness in the PNS ejecta…

We present a review of the possible sources for r-process nuclei. It is known that there is as yet no self-consistent mechanism to provide abundant neutrons for a robust r-process in the neutrino-driven winds from nascent neutron stars. We…

Employing high resolution spectra obtained with the near-UV sensitive detector on the Keck I HIRES, supplemented by data obtained with the McDonald Observatory 2-d coude, we have performed a comprehensive chemical composition analysis of…