J/A+A/610/A66ivo://CDS.VizieR/J/A+A/610/A66doi:10.26093/cds/vizier.36100066CDSCasamiquela L.Carrera R.Balaguer-Nunez L.Jordi C.Chiappini C.,Anders F.Antoja T.Miret-Roig N.Romero-Gomez M.Blanco-Cuaresma S.,Pancino E.Aguado D.S.del Pino A.Diaz-Perez L.Gallart C.2018-12-05T13:09:13Z2018-03-02T16:24:25ZCDS support team

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

cds-question@unistra.fropen-star-clusterschemical-abundancesline-intensitiesThe stellar [{alpha}/Fe] abundance is sometimes used as a proxy for stellar age, following standard chemical evolution models for the Galaxy, as seen by different observational results. In this work we show that the Open Cluster NGC6705/M11 has a significant {alpha}-enhancement [{alpha}/Fe]>0.1dex, despite its young age (~300Myr), challenging the current paradigm.}{We use high resolution (R$>65,000$) high signal-to-noise (~70) spectra of 8 Red Clump stars, acquired within the OCCASO survey. We determine very accurate chemical abundances of several {alpha} elements, using an equivalent width methodology (Si, Ca and Ti), and spectral synthesis fits (Mg and O). We obtain [Si/Fe]=0.13+/-0.05, [Mg/Fe]=0.14+/-0.07, [O/Fe]=0.17+/-0.07, [Ca/Fe]=0.06+/-0.05 and [Ti/Fe]=0.03+/-0.03. Our results place these cluster within the group of young [{alpha}/Fe]-enhanced field stars recently found by several authors in the literature. The ages of our stars have an uncertainty of around 50Myr, much more precise than for field stars. By integrating the cluster's orbit in several non-axisymmetric Galactic potentials, we establish the M11's most likely birth radius to lie between 6.8-7.5kpc from the Galactic center, not far from its current position. With the robust Open Cluster age scale, our results prove that a moderate [{alpha}/Fe]-enhancement is no guarantee for a star to be old, and that not all {alpha}-enhanced stars can be explained with an evolved blue straggler scenario. Based on our orbit calculations, we further argue against a Galactic bar origin of M11.2018A&A...610A..66Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/610/A66CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/513/A29 : RACE-OC project: M11 (NGC6705) (Messina+, 2010)J/A+A/569/A17 : Gaia-ESO Survey: NGC6705 (Cantat-Gaudin+, 2014)J/A+A/573/A55 : Gaia-ESO Survey: Tr 20, NGC4815, NGC6705 (Tautvaisiene+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/610/A66https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/610/A66http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/610/A66https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/610/A66https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/610/A66http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/610/A66GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/610/A66/table1 (Details of the observed stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/610/A66/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/610/A66/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/610/A66/table1?GETtext/xml+votable180.050000true282.81537917-6.304019440.0055555555555555566/30215https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/610/A66?format=asciidefaultJ/A+A/610/A66/table2*Equivalent widths of CaI, SiI and TiI linesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLambdaWavelength of the line0.1nmem.wl;spect.linedoubleElementName of the chemical speciesmeta.id;meta.maincharloggfLogarithm of the oscillation strengthphys.atmol.collStrengthfloatEPExcitation potentialeVphys.atmol.excitationfloatEW0660H? Equivalent width of the spectrum W0660_HER0.1pmspect.line.eqWidthintnullableEW0669H? Equivalent width of the spectrum W0669_HER0.1pmspect.line.eqWidthintnullableEW0686H? Equivalent width of the spectrum W0686_HER0.1pmspect.line.eqWidthintnullableEW0779H? Equivalent width of the spectrum W0779_HER0.1pmspect.line.eqWidthintnullableEW0779F? Equivalent width of the spectrum W0779_FIE0.1pmspect.line.eqWidthintnullableEW0916H? Equivalent width of the spectrum W0916_HER0.1pmspect.line.eqWidthintnullableEW1184H? Equivalent width of the spectrum W1184_HER0.1pmspect.line.eqWidthintnullableEW1184F? Equivalent width of the spectrum W1184_FIE0.1pmspect.line.eqWidthintnullableEW1256H? Equivalent width of the spectrum W1256_HER0.1pmspect.line.eqWidthintnullableEW1423H? Equivalent width of the spectrum W1423_HER0.1pmspect.line.eqWidthintnullableEW1423F? Equivalent width of the spectrum W1423_FIE0.1pmspect.line.eqWidthintnullableJ/A+A/610/A66/table1Details of the observed starsr_Class1Reference for Class1 (2)meta.ref;pos.framecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name from WEBDA (WNNNN)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainVmagV magnitude from literature (from literature)magphot.mag;em.opt.VfloatPmembProbability of membership from proper motion (from McNamara et al., 1977A&AS...27..117M)stat.probabilityfloatClass1[M SM] Classification from radial velocity (1)meta.code.membercharClass2[M SM] Classification from radial velocity (1)meta.code.membercharr_Class2Reference for Class2 (2)meta.ref;pos.framecharClass3[M SM] Classification from radial velocity (1)meta.code.membercharr_Class3Reference for Class3 (2)meta.ref;pos.framecharInstInstrumentmeta.id;instrcharSNRSignal-to-noise ratio of the spectrumstat.snrintTeffEffective temperature from spectroscopic analysisKphys.temperature.effectiveinte_Teffrms uncertainty on TeffKstat.error;phys.temperature.effectiveintloggSurface gravity from spectroscopic analysislog(cm.s**-2)phys.gravityfloate_loggrms uncertainty on logglog(cm.s**-2)stat.errorfloatvtMicroturbulent velocity from EWkm/sphys.velocfloate_vtrms uncertainty on vtkm/sstat.errorfloatRVRadial velocity from spectroscopic analysiskm/sphys.veloc;pos.heliocentricfloate_RVrms uncertainty on RVkm/sstat.errorfloat[Fe/H]Metallicity from EWphys.abund.Zfloate_[Fe/H]rms uncertainty on [Fe/H]stat.error;phys.abund.FefloatLabelName of the column in table2 with equivalent width datameta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar