Related papers: Galactic evolution of rapid neutron capture proces…
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…
Context. Metal-poor massive stars are supposed to be progenitors of certain supernovae, gamma-ray bursts and compact object mergers, potentially contributing to the early epochs of the Universe with their strong ionizing radiation. However,…
A possible mechanism for the formation of heavy-mass elements in supernovae is the rapid neutron-capture-mechanism (r-process). It depends upon the electron-fraction $Y_e$, a quantity which is determined by beta-decay-rates. In this paper,…
We examine the contribution of electron-capture supernovae (ECSNe), low-mass SNe from collapsing Fe cores (FeCCSNe), and rotating massive stars to the chemical composition of the Galaxy. Our model includes contributions to chemical…
Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this paper, we describe the strong…
From newly-obtained high-resolution, high signal-to-noise ratio spectra the abundances of the elements La and Eu have been determined over the stellar metallicity range -3<[Fe/H]<+0.3 in 159 giant and dwarf stars. Lanthanum is predominantly…
We follow the Galactic enrichment of three easily observed light n-capture elements Sr,Y,and Zr.Input stellar yields have been first separated into their respective main and weak s-process,and r-process components.The s-process yields from…
The evolution of chemical elements in a galaxy is linked to its star formation history. Variations in star formation history are imprinted in the relative abundances of chemical elements produced in different supernova events and asymptotic…
We present detailed chemical abundances of three new bright (V ~ 11), extremely metal-poor ([Fe/H] ~ -3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25…
Intense fluxes of neutrinos are emitted by the hot neutron star produced in a supernova. The electron neutrino and antineutrino capture reactions on neutrons and protons, respectively, provide heating to drive a wind from the hot neutron…
We examine magnetorotationally driven supernovae as sources of $r$-process elements in the early Galaxy. On the basis of thermodynamic histories of tracer particles from a three-dimensional magnetohydrodynamical core-collapse supernova…
Heavy elements like gold, platinum or uranium are produced in the r-process, which needs neutron-rich and explosive environments. Neutron star mergers are a promising candidate for an r-process site. They exhibit three different channels…
We present a detailed analysis of the composition and nucleosynthetic origins of the heavy elements in the metal-poor ([Fe/H]=-1.62+/-0.09) star HD94028. Previous studies revealed that this star is mildly enhanced in elements produced by…
We examine the Pb and Th abundances in 27 metal-poor stars (-3.1 < [Fe/H] < -1.4) whose very heavy metal (Z > 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from HST/STIS, Keck/HIRES,…
Recent studies suggest that the most energetic cosmic rays, exceeding 100 EeV, may primarily consist of $r$-process nuclei. This highlights binary neutron star mergers and collapsars as promising sources of ultra-high-energy cosmic rays…
There have been attempts to fit the abundance patterns of extremely metal-poor stars with supernova nucleosynthesis models for the lighter elements than Zn. On the other hand, observations have revealed that the presence of EMP stars with…
Neutrinos emitted in the coalescence of two neutron stars affect the dynamics of the outflow ejecta and the nucleosynthesis of heavy elements. In this work, we analyze the neutrino emission properties and the conditions leading to the…
The evolution and explosion of metal-free stars with masses 10--100 solar masses are followed, and their nucleosynthetic yields, light curves, and remnant masses determined. When the supernova yields are integrated over a Salpeter initial…
This study probes the chemical abundances of the neutron-capture elements cerium and neodymium in the inner Milky Way from an analysis of a sample of $\sim$2000 stars in the Galactic Bulge/bar spatially contained within $|X_{Gal}|<$5 kpc,…
Recent dynamical analysis based on Gaia data have revealed major accretion events in Milky Way's history. Nevertheless, our understanding of the primordial Galaxy is hindered because the bona fide identification of the most metal-poor and…