Related papers: Chemical Evolution of the Juvenile Universe
We compute the evolution of the abundances of barium and europium in the Milky Way and we compare our results with the observed abundances from the recent UVES Large Program "First Stars". We use a chemical evolution model which already…
Both recent observations and stellar evolution models suggest that pair-instability supernovae (PISNe) could occur in the local Universe, at metallicities below Z_Sun/3. Previous PISN models were mostly produced at very low metallicities in…
Recent detailed simulations of Galactic Chemical Evolution have shown that the heavy elements, in particular [Fe/H], are expected to exhibit a weak, or absent, correlation with stellar ages in the early Galaxy due to the lack of efficient…
Recent observations of solar twin stars with planetary systems like the Sun, have uncovered that these present a peculiar surface chemical composition. This is believed to be related to the formation of earth-like planets. This suggests…
Planetary nebulae are the products of the evolution of low and intermediate mass stars. The chemical property studies of these objects give important information about the elemental abundances as He, O, Ne, Ar, S and their modifications…
Models of primordial and hyper-metal-poor stars with masses similar to the Sun experience an ingestion of protons into the hot core during the core helium flash phase at the end of their red giant branch evolution. This produces a…
Recent spectroscopic measurements in open clusters younger than the Sun, with [Fe/H]>=0, showed that the abundances of neutron-rich elements have continued to increase in the Galaxy after the formation of the Sun, roughly maintaining a…
Big Bang nucleosynthesis produces only light elements and the very first generation stars are thus formed from metal-free clouds. They start the production of heavy elements during their life, and enrich the interstellar medium through…
We have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of type II supernovae. The primary aim was to constrain the conditions for the production of the classical "p-only" isotopes of the light…
Abundances of low-metallicity stars offer a unique opportunity to understand the contribution and conditions of the different processes that synthesize heavy elements. Many old, metal-poor stars show a robust abundance pattern for elements…
Several short-lived radionuclides (SLRs) are know to have existed in the early Solar System (ESS). These species, which typically decay with half-lives of the order of a few million years, can be used to probe the timescale of events…
Context. Low- and intermediate-mass giants undergo a complex chemical evolution that has yet to be observationally probed. The influence of core helium flash on the chemical composition of stellar atmospheres has been an open question since…
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…
Type IIn supernovae (SNe IIn) are hydrogen-rich explosions embedded in dense circumstellar medium (CSM), which gives rise to their characteristic narrow hydrogen emission lines. The nature of their progenitors and pre-explosion mass loss…
The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely…
The production of the heavy stable proton-rich isotopes between 74Se and 196Hg -- the p nuclides -- is due to the contribution from different nucleosynthesis processes, activated in different types of stars. Whereas these processes have…
While the high-entropy wind (HEW) of Type II supernovae remains one of the more promising sites for the rapid neutron-capture (r-) process, hydrodynamic simulations have yet to reproduce the astrophysical conditions under which the latter…
Using results of nucleosynthesis calculations for theoretical core-collapse supernova models with various progenitor's masses, it is shown that abundance patterns of C, Mg, Si, Ca, and H seen in extremely metal-deficient stars with [Fe/H] <…
The properties of supernovae (SNe) are reviewed. It is shown that the observed characteristics of the morphological classes of SNe (types Ia, Ib/c, II) can be explained in terms of two basic explosion mechanisms, i.e. core collapse of…
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…