The most metal-poor stars. III. The metallicity distribution function and carbon-enhanced metal-poor fraction
2013 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 762, no 1, 27- p.Article in journal (Refereed) Published
We examine the metallicity distribution function (MDF) and fraction of carbon-enhanced metal-poor (CEMP) stars in a sample that includes 86 stars with [Fe/H] <= -3.0, based on high-resolution, high signal-to-noise spectroscopy, of which some 32 objects lie below [Fe/H] = -3.5. After accounting for the completeness function, the "corrected" MDF does not exhibit the sudden drop at [Fe/H] = -3.6 that was found in recent samples of dwarfs and giants from the Hamburg/ESO survey. Rather, the MDF decreases smoothly down to [Fe/H] = -4.1. Similar results are obtained from the "raw" MDF. We find that the fraction of CEMP objects below [Fe/H] = -3.0 is 23% +/- 6% and 32% +/- 8% when adopting the Beers & Christlieb and Aoki et al. CEMP definitions, respectively. The former value is in fair agreement with some previous measurements, which adopt the Beers & Christlieb criterion.
Place, publisher, year, edition, pages
2013. Vol. 762, no 1, 27- p.
early universe, Galaxy: formation, Galaxy: halo, nuclear reactions, nucleosynthesis, abundances, stars: abundances
IdentifiersURN: urn:nbn:se:uu:diva-193501DOI: 10.1088/0004-637X/762/1/27ISI: 000313007900027OAI: oai:DiVA.org:uu-193501DiVA: diva2:603121