Related papers: Evolution of low-mass metal-free stars including e…
The first stars hold intrinsic interest for their uniqueness and for their potential importance to galaxy formation, chemical enrichment, and feedback on the intergalactic medium (IGM). The metal-free composition of the first stars…
The first stars likely formed from pristine clouds, marking a transformative epoch after the dark ages by initiating reionisation and synthesising the first heavy elements. Among these, low-mass Population III stars are of particular…
We calculate the evolution of zero-metallicity Population III (Pop III) stars whose mass grows from the initial mass of $\sim 1M_{\odot}$ by accreting the surrounding gases. Our calculations cover a whole evolutionary stages from the…
Context. The recent detection of nitrogen-enhanced, metal-poor galaxies at high redshift by the James Webb Space Telescope has sparked renewed interest in exploring the chemical evolution of carbon, nitrogen, and oxygen (the CNO elements)…
New observations from the Hubble ultra deep field suggest that the star formation rate at z>7 drops off faster than previously thought. Using a newly determined star formation rate for the normal mode of Population II/I stars (PopII/I),…
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…
A PopIII/Pop II transition from massive to normal stars is predicted to occur when the metallicity of the star forming gas crosses the critical range Z_cr = 10^(-5 +/- 1) Z_sun. To investigate the cosmic implications of such process we use…
We explore the possibility of observing Population III (Pop~III) stars, born of the primordial gas. Pop~III stars with masses below $0.8 M_\odot$ should survive to date though are not observed yet, but the existence of stars with low…
Stellar winds from fast-rotating Population III (Pop III) stars have long been suspected to make important contributions to early metal enrichment, as features in the nucleosynthesis of such `spinstars' are consistent with the chemical…
Hydrodynamical cosmological simulations predict that the metal-free Population III (Pop III) stars were likely very massive and, therefore, short-lived. However, they left their chemical imprint on their descendants, which can also have…
We make use of new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova ejecta, and the impact on the chemical composition of the Galactic Halo. Using the…
(shortened) The first couple of stellar generations may have been massive, of order 100 Msun, and to have played a dominant role in galaxy formation and the chemical enrichment of the early Universe. Some fraction of these objects may have…
We describe how star formation is expected to proceed in the early metal-free Universe, focusing on the very first generations of stars. We then discuss how the star formation process may change as the effects of metallicity, external…
We present extensive evolutionary models of stars with initial zero-metallicity, covering a large range of initial masses (i.e. 0.7 <= M <= 100 Msun). Calculations are carried out at constant mass, with updated input physics, and applying…
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…
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…
Although the theoretical study of very low metallicity (Z) and metal-free stars is not new, their importance has recently greatly increased since two related fields have been developing rapidly. The first is cosmological simulations of the…
Very metal-poor stars that have $[\text{Fe}/\text{H}]<-2$ and that are enhanced in C relative to Fe ($[\text{C}/\text{Fe}]>+0.7$) but have no enhancement of heavy elements ($[\text{Ba}/\text{Fe}]<0$) are known as carbon-enhanced metal-poor…
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…
Our current understanding of the chemical evolution of the Universe is that a first generation of stars was formed out of primordial material, completely devoid of metals (Pop III stars). This first population of stars comprised massive…