Search

We discuss the star formation history of the Galaxy, based on the observations of extremely metal-poor stars (EMP) in the Galactic halo, to gain an insight into the evolution and structure formation in the early universe. The initialmass function (IMF) of EMP stars is derived from the observed fraction of carbon-enhanced EXP (CEMP) stars among the EMP survivors, which are thought to originate from the evolution in the close binary systems with mass transfer. Relying upon the theory of the evolution of EMP stars and of their binary evolution, we find that stars of metallicity [Fe/H]

The information on surface abundances in extremely metal‐poor (EMP) stars in the Galactic halo is a useful probe of the early universe. Therefore, it is very important to understand the modification of abundances in EMP stars by internal and/or external pollution through mixing processes and binary interactions in stellar evolution. We computed various sets of model stars for 0.8–9.0–M⊙ in mass and −5< [Fe/H]