Related papers: CNO production in first generation stars
A series of fast rotating models at very low metallicity (Z=1e-8) was computed in order to explain the surface abundances observed at the surface of CEMP stars, in particular for nitrogen. The main results are the following: - Strong mixing…
We investigate the impact of an early population of massive stars on their surroundings. Dissociation of molecular hydrogen by strong UV emission from such stars is expected to produce a global transition in the cooling mechanism of…
Recent hydrodynamical simulations of the late stages of supernova remnant (SNR) evolution have revealed that as they merge with the ambient medium, SNRs implode, leading to the formation of dense clouds in their center. While being highly…
Neutrino losses play a crucial role in the evolution of massive stars. We study the neutrino luminosity of stars ranging from 20 to 90 M_{\odot} from Zero Age Main Sequence (ZAMS) to Fe Core Collapse (FeCC) with different rotation and…
We study cosmological simulations of early structure formation, including non-equilibrium molecular chemistry, metal pollution from stellar evolution, transition from population III (popIII) to population II (popII) star formation,…
We calculate presupernova evolutions and supernova explosions of massive stars (M=13-25 Mo) for various metallicities. We find the following characteristic abundance patterns of nucleosynthesis in the metal-free (Pop III) stars. (1) The…
Very massive stars are thought to be formed in the early Universe because of a lack of cooling process by heavy elements, and might have been responsible for the later evolution of the Universe. We had an interest in vibrational stability…
The present paper discusses the main physical effects produced by stellar rotation on presupernovae, as well as observations which confirm these effects and their consequences for presupernova models. Rotation critically influences the mass…
We investigate the formation of extremely metal-poor (EMP) stars that are observed in the Galactic halo and neighboring ultra-faint dwarf galaxies. Their low metal abundances (${\rm [Fe/H]} < -3$) indicate that their parent clouds were…
We study the role played both by novae and single stars in enriching the ISM of the Galaxy with CNO group nuclei, in the framework of a detailed successful model for the chemical evolution of both the Galactic halo and disc. Once all the…
We study the evolution of gas in HII regions around the first stars after the death of the exciting stars. If the first star in a small halo dies without supernova (SN), subsequent star formation is possible in the same halo. We thus…
We consider the contribution of neutron stars and black holes to the dynamical mass of galactic halos. In particular, we show that if these compact objects were produced by an early generation of stars with initial metallicity less than…
The assembly of supermassive black holes poses a challenge primarily because of observed quasars at high redshift, but additionally because of the current lack of observations of intermediate mass black holes. One plausible scenario for…
Population III (or Pop. III) stars, the first stellar generation built up from metal-free primordial gas, first started to form at redshifts z ~ 30. They formed primarily in small dark matter halos with masses of a few million solar masses.…
Full evolutionary models have been built to follow the phases of asymptotic giant branch evolution with mass loss for metal mass fractions from Z=0.0002 to Z=0.004. For the first time, we find that temperatures close to or even larger than…
Carbon, nitrogen, and oxygen (CNO) are key elements in stellar formation and evolution, and their abundances should also have a significant impact on planetary formation and evolution. We present a detailed spectroscopic analysis of 74…
The chemical enrichment of the early Universe is a crucial element in the formation and evolution of galaxies, and Population III (PopIII) stars must play a vital role in this process. In this study, we examine metal enrichment from massive…
The first stars might have been fast rotators. This would have important consequences for their radiative, mechanical and chemical feedback. We discuss the impact of fast initial rotation on the evolution of massive Population III models…
We investigate the effect of new stellar models, which take rotation into account, computed for very low metallicities on the chemical evolution of the earliest phases of the Milky Way. We check the impact of these new stellar yields on a…
We use detailed nucleosynthesis calculations and a realistic prescription for the environment of the first stars to explore the first episodes of chemical enrichment that occurred during the dark ages. Based on these calculations, we…