J/A+A/687/A229ivo://CDS.VizieR/J/A+A/687/A229doi:10.26093/cds/vizier.36870229CDSMishenina T.Pignatari M.Usenko I.Soubiran C.Thielemann F.-K.,Kniazev A.Yu.Korotin S.A.Gorbaneva T.2024-11-29T20:03:50Z2024-07-19T08:08:38ZCDS support team

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

cds-question@unistra.frpeculiar-variable-starschemically-peculiar-starsline-intensitieschemical-abundancesThe oldest stars in the Milky Way are metal-poor with [Fe/H]<-1.0, and they show peculiar elemental abundances compared to solar. The relative variations of the chemical compositions between stars is also increasing with decreasing stellar metallicity, allowing to reveal the pure signature of unique nucleosynthesis processes. The study of the r-process is for instance one of the main goals of stellar archaeology, and metal-poor stars show an unexpected complexity in the stellar production of the r-process elements in the early Galaxy. In this work we report the atmospheric parameter, the main dynamic properties and the abundances of four metal-poor stars: HE 1523-0901, HD 6268, HD 121135, and HD 195636 (-1.5>[Fe/H]>-3.0). The abundances are derived from spectra obtained with the HRS echelle spectrograph at the Southern African Large Telescope, using both LTE and NLTE approaches, with an average error between 0.10 and 0.20dex. Based on their kinematical properties, we show that HE 1523-0901 and HD 195636 are halo stars with typical high velocities; HD 121135 has a peculiar kinematical behaviour making unclear if it is a halo or an accreted star; and HD 6268 is possibly a rare prototype of very metal-poor thick disk stars. The abundances derived for our stars are compared with theoretical stellar models and with other stars with similar metallicity from the literature.2024A&A...687A.229Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/687/A229CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/687/A229https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/687/A229http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/687/A229https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/687/A229https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/687/A229http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/687/A229GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/687/A229/tablea1Line list, EWs and abundances of CaI, TiI, TiII, CrI, FeI, FeII and NiIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoubleSpeciesAtomic Numbermeta.id;meta.mainfloatElowLower level potentialeVphys.energy;phys.atmol.levelfloatloggfOscillator strengthphys.atmol.oscStrengthfloatEW1? Equivalent line width for HE 1523-09010.1pmspect.line.eqWidthfloatnullablelogA1? Element abundances for HE 1523-0901 (1)phys.atmol.elementfloatnullableEW2? Equivalent line width for HD 62680.1pmspect.line.eqWidthfloatnullablelogA2? Element abundances for HD 6268 (1)phys.atmol.elementfloatnullableEW3? Equivalent line width for HD 1211350.1pmspect.line.eqWidthfloatnullablelogA3? Element abundances for HD 121135 (1)phys.atmol.elementfloatnullableEW4? Equivalent line width for HD 1956360.1pmspect.line.eqWidthfloatnullablelogA4? Element abundances for HD 195636 (1)phys.atmol.elementfloatnullableJ/A+A/687/A229/tableb1*Line list, and abundances of neutron-capture elementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoubleSpeciesAtomic Numbermeta.id;meta.mainfloatElowLower level potentialeVphys.energy;phys.atmol.levelfloatloggfOscillator strengthphys.atmol.oscStrengthfloatlogA1? Element abundances for HE 1523-0901 (1)phys.atmol.elementfloatnullablelogA2? Element abundances for HD 6268 (1)phys.atmol.elementfloatnullablelogA3? Element abundances for HD 121135 (1)phys.atmol.elementfloatnullable