相关论文: First Star Survivors as Metal-Rich Halo Stars that…

The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars (with metallicities down to [Fe/H]\sim-5.5) are relics from the…

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 abundance patterns of the most metal-poor stars in the Galactic halo and small dwarf galaxies provide us with a wealth of information about the early Universe. In particular, these old survivors allow us to study the nature of the first…

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…

The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals')…

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 lack of observations of abundance patterns originating in pair-instability supernovae has been a long-standing problem in relation to the first stars. This class of supernovae is expected to have an abundance pattern with a strong…

The oldest, most metal-poor stars in the Galactic halo and satellite dwarf galaxies present an opportunity to explore the chemical and physical conditions of the earliest star forming environments in the Universe. We review the fields of…

The cosmic microwave background and the cosmic expansion can be interpreted as evidence that the Universe underwent an extremely hot and dense phase about 14 Gyr ago. The nucleosynthesis computations tell us that the Universe emerged from…

Two alternative scenarios concerning the origin and evolution of extremely metal-poor halo stars are investigated. The first one assumes that the stars have been completely metal-free initially and produced observed carbon and nitrogen…

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…

There is a longstanding discussion about whether low mass stars can form from pristine gas in the early Universe. A particular point of interest is whether we can find surviving pristine stars from the first generation in our local…

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 argue that extreme metal-poor stars show a high dispersion in metallicity, because their abundances are the outcome of very few supernova events. Abundance anomalies should appear because of the discrete range of progenitor masses. There…

We investigate the conditions under which the first low-mass stars formed in the universe by confronting theoretical predictions governing the transition from massive Population III to low-mass Population II stars with recent observational…

The first generation of stars was formed from primordial gas. Numerical simulations suggest that the first stars were predominantly very massive, with typical masses M > 100 Mo. These stars were responsible for the reionization of the…

Metal-poor stars hold the key to our understanding of the origin of the elements and the chemical evolution of the Universe. This chapter describes the process of discovery of these rare stars, the manner in which their surface abundances…

Evolution of first population of massive metal-free binary stars is followed. Due to the low metallicity, the stars are allowed to form with large initial masses and to evolve without significant mass loss. Evolution at zero metallicity,…

The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few…

The most metal-poor stars found in the Galaxy and in nearby galaxies are witnesses of the early evolution of the Universe. In a general picture in which we expect the metallicity to increase monotonically with time, as a result of the metal…