Very metal-poor stars, observed in the ESO large program (ESO-LP, sample of Cayrel et al., 2004), are analyzed in a cosmological context, with a special emphasis on carbon-enhanced metal-poor stars (CEMPS; Christlieb et al. 2002, Frebel et al. 2005, Aoki et al. 2006). We model the IMF and SFR of three populations of stars, PopIII.1, PopIII.2 and PopII, and follow the resulting element abundances in the interstellar medium (ISM). The evolution of the abundances of different elements and the metallicity distribution function (MDF) are respectively predicted and compared to i) the ESO-LP data, as a function of redshift, and ii) to the HK and the Hamburg/ESO (HES) surveys, as a function of metallicity. In this context, each star can be uniquely associated with a redshift (i.e. a formation time) via its abundance pattern, which enables us to recast them in a cosmological scenario with a bimodal star formation history.
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