相关论文: Evidence for an aspherical Population III supernov…
We explore a scenario where metal-poor globular clusters (GCs) are enriched by the first supernovae in the Universe. If the first stars in a 10^7 Msun dark halo were very massive (>180 Msun), then a pair instability supernova from a single…
The metal-poor stars in the Galactic halo are thought to show the imprints of the first (PopIII) stars, and thus provide a glance at the first episodes of star formation. In this work, we aim at understanding whether all very metal-poor…
We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H]<-6.3, based on a high-resolution (R~35,000) Magellan/MIKE spectrum. The star was originally found to have [Fe/H]< -6.6 based on…
The chemical abundance patterns observed in metal-poor Galactic halo stars contain the signature of the first supernovae, and thus allows us to probe the first stars that formed in the universe. We construct a theoretical model for the…
The external pollution of the first stars in the Galaxy is investigated. The first stars were born in clouds composed of the pristine gas without heavy elements. These stars accreted gas polluted with heavy elements while they still…
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…
We present a new analysis of the abundances observed in extremely metal poor stars based on both a new generation of theoretical presupernova models and explosions of zero metallicity massive stars and a new abundance analysis of an…
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 investigate the relationship between explosion energy and nucleosynthesis in Population III supernovae and provide nucleosynthetic results for the explosions of stars with progenitor masses of $15\,\mathrm{M}_\odot$,…
The era of the universe's first (Population III) stars is essentially unconstrained by observation. Ultra-luminous and massive stars from this time altered the chemistry of the cosmos, provided the radiative scaffolding to support the…
We present a simulation of the formation of the earliest Population II stars, starting from cosmological initial conditions and ending when metals created in the first supernovae are incorporated into a collapsing gas-cloud. This occurs…
Recent high-resolution spectroscopy with the James Webb Space Telescope (JWST) has confirmed the presence of a strong He II, $\lambda1640$ emitting clump in the vicinity of GN-z11, with only upper limits on its metallicity. To explain the…
We examine the dynamical evolution and statistical properties of the supernova ejecta of massive primordial stars in a cosmological framework to determine whether this first population of stars could have enriched the universe to the levels…
We present a new abundance analysis of HE 1327-2326, the currently most iron-poor star, based on observational data obtained with VLT/UVES. We correct the 1D LTE abundances for 3D effects to provide an abundance pattern that supersedes…
A stochastic model of the chemical enrichment of metal-poor systems by core-collapse (Type II) supernovae is presented, allowing for large-scale mixing of the enriched material by turbulent motions and cloud collisions in the interstellar…
Finding the first generation of stars formed out of pristine gas in the early Universe, known as Population III (PopIII) stars, is one of the most important goals of modern astrophysics. Recent models have suggested that PopIII stars may…
Metal enrichment by the first-generation (Pop III) stars is the very first step of the matter cycle in the structure formation and it is followed by the formation of extremely metal-poor (EMP) stars. To investigate the enrichment process by…
The very peculiar abundance patterns observed in extremely metal-poor (EMP) stars can not be explained by ordinary supernova nucleosynthesis but can be well-reproduced by nucleosynthesis in hyper-energetic and hyper-aspherical explosions,…
The most iron-deficient stars in the Milky Way provide important observational constraints on the nature of astrophysical objects that have enriched the primordial gas with heavy elements from which these stars were formed. Among them, the…
We report a detailed abundance analysis for HE0107-5240, a halo giant with [Fe/H]_NLTE=-5.3. This star was discovered in the course of follow-up medium-resolution spectroscopy of extremely metal-poor candidates selected from the digitized…