J/A+A/403/1105ivo://CDS.VizieR/J/A+A/403/1105doi:10.26093/cds/vizier.34031105CDSFrancois P.Depagne E.Hill V.Spite M.Spite F.Plez B.,Beers T.C.Barbuy B.Cayrel R.Andersen J.Bonifacio P.Molaro P.,Nordstroem F.Primas B.2003-06-01T07:44:20Z2003-06-01T07:44:14ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgiant-starshalo-starschemically-peculiar-starsline-intensitiesThis paper reports detailed abundance analyses for four extremely metal-poor (XMP) giant stars with [Fe/H]<-3.8, based on high-resolution, high- S/N spectra from the ESO VLT (Kueyen/UVES) and LTE model atmosphere calculations. The derived [{alpha}/Fe] ratios in our sample exhibit a small dispersion, confirming previous findings in the literature, i.e. a constant overabundance of the {alpha}-elements with a very small (if any) dependence on [Fe/H]. In particular, the very small scatter we determine for [Si/Fe] suggests that this element shows a constant overabundance at very low metallicity, a conclusion which could not have been derived from the widely scattered [Si/Fe] values reported in the literature for less metal-poor stars. For the iron-peak elements, our precise abundances for the four XMP stars in our sample confirm the decreasing trend of Cr and Mn with decreasing [Fe/H], as well as the increasing trend for Co and the absence of any trend for Sc and Ni. In contrast to the significant spread of the ratios [Sr/Fe] and [Ba/Fe], we find [Sr/Ba] in our sample to be roughly solar, with a much lower dispersion than previously found for stars in the range -3.5<[Fe/H]<-2.5.2003A&A...403.1105Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/403/1105CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/123/639 : UBV photometry of metal-weak candidates (Norris+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/403/1105https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/403/1105http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/403/1105https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/403/1105https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/403/1105http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/403/1105GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/403/1105/table5Equivalent widths for program starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintElementChemical element and ionization stagephys.atmol.elementcharLambdaWavelength in Angstroem0.1nmem.wldoubleEPLine Excitation potential of the line energyeVphys.energy;phys.atmol.excitationfloatloggfOscillator strength (1)phys.atmol.wOscStrengthfloatEW1? Equivalent width of the line for CD-38 2450.1pmspect.line.eqWidthfloatnullableEW2? Equivalent width of the line for CS 22885-0960.1pmspect.line.eqWidthfloatnullableEW3? Equivalent width of the line for BS 16467-0620.1pmspect.line.eqWidthfloatnullableEW4? Equivalent width of the line for CS 22172-0020.1pmspect.line.eqWidthfloatnullable