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Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2004

First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy

V. Hill
Bertrand Plez
T. Beers
  • Fonction : Auteur
Francesca Primas
  • Fonction : Auteur
J. Andersen
  • Fonction : Auteur
B. Barbuy
  • Fonction : Auteur
P. Bonifacio
P. Molaro
  • Fonction : Auteur
B. Nordstrom
  • Fonction : Auteur

Résumé

In the framework of an ESO Large Programme high quality spectra of 70 very metal-poor dwarfs and giants were obtained with the VLT-UVES combination. This paper reports the detailed analyses of the 35 giants of the sample. At the exception of a few template stars, all the targets are from the H&K Beers et al. survey. No less than 22 stars have [Fe/H] below -3.0. The imprint of yields of the first galactic or protogalactic supernovae is sampled in the photospheres of these stars. If [C/Fe], [Na/Fe] and [Al/Fe] show a spread significantly above the observational scatter, several abundance ratios present an amazing low scatter when plotted against [Fe/H], as [Cr/Fe] but also odd elements, as [K/Fe] or [Sc/Fe]. The abundance of oxygen has been derived from the [O I] line for 16 of these giants, in spite of the extreme weakness of the line. No significant slope with [Fe/H] is found. Similar plots have been made using Mg instead of Fe as reference element. With Mg, no clear trend with metallicity is obvious below [Mg/H]=-3., except perhaps for [Zn/Mg]. It is contemplated that the mild slope found in the very low scatter diagram [Cr/Fe] versus [Fe/H] might be spurious due for example to the LTE approximation plus use of 1-D models. This would relax the absence of scatter in the dilution of the SN ejectas within the ambient medium, as needed if [Fe/H] is a well defined function of [Cr/Fe].

Dates et versions

hal-00014526 , version 1 (27-11-2005)

Identifiants

Citer

R. Cayrel, E. Depagne, M. Spite, V. Hill, F. Spite, et al.. First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy. Astronomy and Astrophysics - A&A, 2004, 416, pp.1117-1138. ⟨hal-00014526⟩
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