J/A+A/585/A102ivo://CDS.VizieR/J/A+A/585/A102doi:10.26093/cds/vizier.35850102CDSYan H.L.Shi J.R.Nissen P.E.Zhao G.2017-09-20T05:13:47Z2016-05-10T13:42:47ZCDS support team

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

cds-question@unistra.frchemical-abundancesTwo distinct halo populations were found in the solar neighborhood by a series of works. They can be clearly separated by [{alpha}/Fe] and several other elemental abundance ratios including [Cu/Fe]. Very recently, a non-local thermodynamic equilibrium (non-LTE) study revealed that relatively large departures exist between LTE and non-LTE results in copper abundance analysis. The study also showed that non-LTE effects of neutral copper vary with stellar parameters and thus affect the [Cu/Fe] trend. We aim to derive the copper abundances for the stars from the sample of Nissen & Schuster (2010A&A...511L..10N) with both LTE and non-LTE calculations. Based on our results, we study the non-LTE effects of copper and investigate whether the high-{alpha} population can still be distinguished from the low-{alpha} population in the non-LTE [Cu/Fe] results. Our differential abundance ratios are derived from the high-resolution spectra collected from VLT/UVES and NOT/FIES spectrographs. Applying the MAFAGS opacity sampling atmospheric models and spectrum synthesis method, we derive the non-LTE copper abundances based on the new atomic model with current atomic data obtained from both laboratory and theoretical calculations. The copper abundances determined from non-LTE calculations are increased by 0.01 to 0.2dex depending on the stellar parameters compared with the LTE results. The non-LTE [Cu/Fe] trend is much flatter than the LTE one in the metallicity range -1.6<[Fe/H]<-0.8. Taking non-LTE effects into consideration, the high- and low-{alpha} stars still show distinguishable copper abundances, which appear even more clear in a diagram of non-LTE [Cu/Fe] versus [Fe/H]. The non-LTE effects are strong for copper, especially in metal-poor stars. Our results confirmed that there are two distinct halo populations in the solar neighborhood. The dichotomy in copper abundance is a peculiar feature of each population, suggesting that they formed in different environments and evolved obeying diverse scenarios.2016A&A...585A.102Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/585/A102CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/585/A102https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/585/A102http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/585/A102https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/585/A102https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/585/A102http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/585/A102GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/585/A102/tablea1 (LTE and non-LTE copper abundance ratios [Cu/Fe] for stars with VLT/UVES spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/585/A102/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/585/A102/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/585/A102/tablea1?GETtext/xml+votable180.050000true178.8685744-22.38703690.005555555555555556Cone search capability for table J/A+A/585/A102/tablea2 (*LTE and non-LTE copper abundance ratios [Cu/Fe] for stars with NOT/FIES spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/585/A102/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/585/A102/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/585/A102/tablea2?GETtext/xml+votable180.050000true186.74942641.56622310.0055555555555555566/200 208 436 758 953 1053 1425 1614 2839 4603 5622 6681 7286 8235 9537 9831 10313 12451 12793 13162 13348 14059 17245 17332 17726 17782 18053 19347 19385 21926 22118 22754 22909 23015 23096 23978 24442 24775 24824 24827 24942 25444 26292 27323 27826 27975 28258 28265 28459 29006 29490 29765 30196 30233 30296 31470 31503 31874 32100 32335 33273 33508 37232 38288 38986 39157 39647 40716 40924 41721 43310 43641 44281 44653 46053 48394 48736https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/585/A102?format=asciidefaultJ/A+A/585/A102/tablea1LTE and non-LTE copper abundance ratios [Cu/Fe] for stars with VLT/UVES spectraSimbadNameSimbad column added by the CDSmeta.idcharStarStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_Star[a] a for stars having NOT/FIES and VLT/UVES spectrameta.notecharTeff? Effective temperatureKphys.temperature.effectiveintnullablelogg? Surface gravitylog(cm.s**-2)phys.gravityfloatnullable[Fe/H]? Metallicityphys.abund.Zfloatnullablevt? Microturbulent velocitykm/sphys.velocfloatnullable[a/Fe]? [alpha/Fe] abundance (2)phys.abundfloatnullable5105ALLTE Abundance ratios derived from CuI 5105{AA} linephys.abundfloat5218AL? LTE Abundance ratios derived from CuI 5218{AA} linephys.abundfloatnullable5782AL? LTE Abundance ratios derived from CuI 5782{AA} linephys.abundfloatnullable[Cu/Fe]LLTE Abunbance [Cu/Fe]phys.abundfloate_[Cu/Fe]Lrms uncertainty on [Cu/Fe]Lstat.error;phys.abundfloat5105ANNon-LTE Abundance ratios derived from CuI 5105{AA} linephys.abundfloat5218AN? Non-LTE Abundance ratios derived from CuI 5218{AA} linephys.abundfloatnullable5782AN? Non-LTE Abundance ratios derived from CuI 5782{AA} linephys.abundfloatnullable[Cu/Fe]NNon-LTE Abunbance [Cu/Fe]phys.abundfloate_[Cu/Fe]Nrms uncertainty on [Cu/Fe]Nstat.error;phys.abundfloatClassClassification (1)meta.code.classchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/585/A102/tablea2*LTE and non-LTE copper abundance ratios [Cu/Fe] for stars with NOT/FIES spectraSimbadNameSimbad column added by the CDSmeta.idcharStarStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_Star[a] a for stars having NOT/FIES and VLT/UVES spectrameta.notecharTeff? Effective temperatureKphys.temperature.effectiveintnullablelogg? Surface gravitylog(cm.s**-2)phys.gravityfloatnullable[Fe/H]? Metallicityphys.abund.Zfloatnullablevt? Microturbulent velocitykm/sphys.velocfloatnullable[a/Fe]? [alpha/Fe] abundance (2)phys.abundfloatnullable5105ALLTE Abundance ratios derived from CuI 5105{AA} linephys.abundfloat5218AL? LTE Abundance ratios derived from CuI 5218{AA} linephys.abundfloatnullable5782AL? LTE Abundance ratios derived from CuI 5782{AA} linephys.abundfloatnullable[Cu/Fe]LLTE Abunbance [Cu/Fe]phys.abundfloate_[Cu/Fe]Lrms uncertainty on [Cu/Fe]Lstat.error;phys.abundfloat5105ANNon-LTE Abundance ratios derived from CuI 5105{AA} linephys.abundfloat5218AN? Non-LTE Abundance ratios derived from CuI 5218{AA} linephys.abundfloatnullable5782AN? Non-LTE Abundance ratios derived from CuI 5782{AA} linephys.abundfloatnullable[Cu/Fe]NNon-LTE Abunbance [Cu/Fe]phys.abundfloate_[Cu/Fe]Nrms uncertainty on [Cu/Fe]Nstat.error;phys.abundfloatClassClassification (1)meta.code.classchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main