Related papers: The r-process in Magnetorotational Supernovae
We present an abundance analysis based on high resolution spectra of 8 stars selected to span the full range in metallicity in the Draco dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.5 to -3.0 dex. Combining…
The massive First Stars (the first ones to contribute to the chemical enrichment of the Universe due to their short lifetimes) are long dead, and even though efforts to directly observe them in high redshift galaxies are underway, a step…
The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and…
The chemical abundances of the metal-poor stars in the stellar stream provide important information for setting constraints on models of neutron-capture processes. The study of these stars could give us a better understanding of r-process…
An overview of the sources for heavy elements in the early Galaxy is given. It is shown that observations of abundances in metal-poor stars can be used along with a basic understanding of stellar models to guide the search for the source of…
We present a stochastic model based on the Monte Carlo technique to study the inhomogeneous chemical evolution of the Galactic halo. In particular, we consider the local enrichment and subsequent mixing of the interstellar gas resulting…
Recent studies of heavy r-process elements in low [Fe/H] halo stars have suggested that an initial population of metal-free very massive stars (VMSs) may be required to provide early Fe enrichment without coproducing heavy r nuclei. We find…
Stellar abundances reveal non-monotonic [Y/Eu] and [Sr/Eu] evolution, a systematic decline with increasing [Eu/H] at low metallicity, a minimum at $[\rm{Eu/H}] \sim -0.3$ and then a rise at high metallicity. This behavior requires at least…
An early history of metal enrichment in the Galactic halo is studied. We investigate chemical inhomogeneity by using a stochastic chemical evolution model. The model confronts with metallicity distribution function of long-lived halo stars…
The abundance patterns of metal-poor stars provide us a wealth of chemical information about various stages of the chemical evolution of the Galaxy. In particular, these stars allow us to study the formation and evolution of the elements…
The chemical abundances of metal-poor stars are an excellent test bed by which to set new constraints on models of neutron-capture processes at low metallicity. Some r-process-rich (hereafter r-rich) metal-poor stars, such as HD221170, show…
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…
We present 3D hydrodynamical simulations aimed to study the dynamical and chemical evolution of the interstellar medium in dwarf spheroidal galaxies. This evolution is driven by the explosions of Type II and Type Ia supernovae, whose…
We present detailed chemical abundances for 99 red-giant branch stars in the centre of the Sculptor dwarf spheroidal galaxy, obtained from high-resolution VLT/FLAMES spectroscopy. This includes abundances of Li (detected in 1 out of 99…
Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major…
Meteoritic abundances of r-process elements are analyzed to deduce the history of chemical enrichment by r-process from the beginning of disk formation to the present time in the solar vicinity, by combining the abundance information from…
We study the production of barium (Ba) and strontium (Sr) in ultrafaint dwarf galaxies (UFDs). Both r- and s- processes produce these elements, and one can infer the contribution of the r-process from the characteristic r-process abundance…
The third r-process peak (Os, Ir, Pt) is poorly understood due to observational challenges, with spectral lines located in the blue or near-ultraviolet region of stellar spectra. These challenges need to be overcome for a better…
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…
The supernova yields of r-process elements are obtained as a function of the mass of their progenitor stars from the abundance patterns of extremely metal-poor stars on the left-side [Ba/Mg]-[Mg/H] boundary with a procedure proposed by…