J/A+A/619/A178ivo://CDS.VizieR/J/A+A/619/A178doi:10.26093/cds/vizier.36190178CDSBarbuy B.Muniz L.Ortolani S.Ernandes H.Dias B.Saviane I.,Kerber L.Bica E.Perez-Villegas A.Rossi L.Held E.V.2019-01-07T08:49:10Z2018-11-21T08:20:29ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyglobular-star-clustersgiant-starschemical-abundancesNGC 6558 is a bulge globular cluster with a blue horizontal branch (BHB), combined with a metallicity of [Fe/H]~-1.0. It is similar to HP 1 and NGC 6522, which could be among the oldest objects in the Galaxy. Element abundances in these clusters could reveal the nature of the first supernovae. We aim to carry out detailed spectroscopic analysis for four red giants of NGC 6558, in order to derive the abundances of the light elements C, N, O, Na, Al, the {alpha}-elements Mg, Si, Ca, Ti, and the heavy elements Y, Ba, and Eu. High-resolution spectra of four stars with FLAMES-UVES@VLT UT2-Kueyen were analysed. Spectroscopic parameter-derivation was based on excitation and ionization equilibrium of FeI and FeII. This analysis results in a metallicity of [Fe/H]=-1.17+/-0.10 for NGC 6558. We find the expected {alpha}-element enhancements in O and Mg with [O/Fe]=+0.40, [Mg/Fe]=+0.33, and low enhancements in Si and Ca. Ti has a moderate enhancement of [Ti/Fe]=+0.22. The r-element Eu appears very enhanced with a mean value of [Eu/Fe]=+0.63. The first peak s-elements Y and Sr are also enhanced, these results have however to be treated with caution, given the uncertainties in the continuum definition; the use of neutral species (Sr I, YI), instead of the dominant ionized species is another source of uncertainty. Ba appears to have a solar abundance ratio relative to Fe. NGC 6558 shows an abundance pattern that could be typical of the oldest inner bulge globular clusters, together with the pattern in the similar clusters NGC 6522 and HP 1. They show low abundances of the odd-Z elements Na and Al, and of the explosive nucleosynthesis {alpha}-elements Si, Ca, and Ti. The hydrostatic burning {alpha}-elements O and Mg are normally enhanced as expected in old stars enriched with yields from core-collapse supernovae, and the iron-peak elements Mn, Cu, Zn show low abundances, which is expected forMn and Cu, but not for Zn. Finally, the cluster trio NGC 6558, NGC 6522 and HP 1 have relatively high abundances of first-peak heavy elements, variable second-peak element Ba, and the r-element Eu is enhanced. The latter is particularly high in NGC 6558.2018A&A...619A.178Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/619/A178CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/619/A178https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/619/A178http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/619/A178https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/619/A178https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/619/A178http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/619/A178GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/619/A178/stars (List of studied stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/619/A178/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/619/A178/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/619/A178/stars?GETtext/xml+votable180.050000true272.59261667-31.762038890.0055555555555555566/28768https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/619/A178?format=asciidefaultJ/A+A/619/A178/starsList of studied starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoStar numbermeta.idint2MASS2MASS name (HHMMSSss+DDMMSSs)meta.id;meta.maincharRAJ2000right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainEWDisplay the equivalent widthsmeta.ref.urlchar[X/Fe]Display the [Fe/X] abundancesmeta.ref.urlcharJ/A+A/619/A178/tablea1FeI and FeII lines employed, their wavelengths, excitation potential, oscillator strengths and van der Waals broadening constant C_6_ adoptedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonAtomic species (FeI or FeII)phys.atmol.ionStagecharlambdaWavelength0.1nmem.wlfloatchiexExcitation potential {chi}_ex_eVphys.atmol.excitationfloatloggfOscillator strengthphys.atmol.oscStrengthfloatC6Van der Waals broadening constant C_6_arith.zpdoubleEW283? Equivalent Width for star 2830.1nmspect.line.eqWidthfloatnullableEW364? Equivalent Width for star 3640.1nmspect.line.eqWidthfloatnullableEW1072? Equivalent Width for star 10720.1nmspect.line.eqWidthfloatnullableEW1160? Equivalent Width for star 11600.1nmspect.line.eqWidthfloatnullableJ/A+A/619/A178/tablea2*Abundance ratios [X/Fe] of C, N, O, odd-Z elements Na, Al, alpha-elements O, Mg, Si, Ca, Ti, and heavy elements Eu, Ba, La, Y, Sr, and atomic parameters adopted.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonAtomic speciesphys.atmol.ionStagecharlambdaWavelength0.1nmem.wldoublechiex? Excitation potential {chi}_ex_eVphys.atmol.excitationfloatnullableloggf? Oscillator strengthphys.atmol.oscStrengthfloatnullable[X/Fe]283? Logarithmic abundance relative to Iron [X/Fe] for star 283phys.abundfloatnullableu_[X/Fe]283Uncertainty flag on [X/Fe]283meta.code.error;phys.abundchar[X/Fe]364? Logarithmic abundance relative to Iron [X/Fe] for star 364phys.abundfloatnullableu_[X/Fe]364Uncertainty flag on [X/Fe]364meta.code.error;phys.abundchar[X/Fe]1072? Logarithmic abundance relative to Iron [X/Fe] for star 1072phys.abundfloatnullableu_[X/Fe]1072Uncertainty flag on [X/Fe]1072meta.code.error;phys.abundchar[X/Fe]1160? Logarithmic abundance relative to Iron [X/Fe] for star 1160phys.abundfloatnullableu_[X/Fe]1160Uncertainty flag on [X/Fe]1160meta.code.error;phys.abundchar