J/MNRAS/481/373ivo://CDS.VizieR/J/MNRAS/481/373doi:10.26093/cds/vizier.74810373CDSMacLean B.T.Campbell S.W.Amarsi A.M.Nordlander T.Cottrell P.L.,De Silva G.M.Lattanzio J.Constantino T.D'Orazi V.Casagrande L.2024-08-18T20:21:51Z2022-07-04T12:46:38ZCDS support team

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

cds-question@unistra.frchemical-abundancesglobular-star-clustersgiant-starsinfrared-photometryvisible-astronomybroad-band-photometrySeveral recent spectroscopic investigations have presented conflicting results on the existence of Na-rich asymptotic giant branch (AGB) stars in the Galactic globular cluster M 4 (NGC 6121). The studies disagree on whether or not Na-rich red giant branch (RGB) stars evolve to the AGB. For a sample of previously published HERMES/AAT AGB and RGB stellar spectra, we present a re-analysis of O, Na, and Fe abundances, and a new analysis of Mg and Al abundances; we also present CN band strengths for this sample, derived from low-resolution AAOmega spectra. Following a detailed literature comparison, we find that the AGB samples of all studies consistently show lower abundances of Na and Al, and are weaker in CN, than RGB stars in the cluster. This is similar to recent observations of AGB stars in NGC 6752 and M 62. In an attempt to explain this result, we present new theoretical stellar evolutionary models for M 4; however, these predict that all stars, including Na-rich RGB stars, evolve on to the AGB. We test the robustness of our abundance results using a variety of atmospheric models and spectroscopic methods; however, we do not find evidence that systematic modelling uncertainties can explain the apparent lack of Na-rich AGB stars in M 4. We conclude that an unexplained, but robust, discordance between observations and theory remains for the AGB stars in M 4.2018MNRAS.481..373Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/481/373CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/233 : The Two Micron All Sky Survey (2MASS)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/481/373https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/481/373http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/481/373https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/481/373https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/481/373http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/481/373GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/481/373/table1 (M4 target details)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/481/373/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/481/373/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/481/373/table1?GETtext/xml+votable180.050000true245.9905-26.38213890.0055555555555555566/429557.952274030004205e-20 6.118840631666147e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/481/373?format=asciiOpticalInfrareddefaultJ/MNRAS/481/373/table1M4 target detailsSimbadSimbad column added by the CDSmeta.ref.urlcharIDTarget ID (1)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeStar type (AGB : asymptotic giant branch star or RGB : red giant branch star)src.classchar2MASS2MASS Name (2MASS JHHMMSSss+DDMMSSsA)meta.idcharVmagV-band magnitude (1)magphot.mag;em.opt.VfloatBmagB-band magnitude (1)magphot.mag;em.opt.BfloatUmag? U-band magnitude (1)magphot.mag;em.opt.UfloatnullableImag? I-band magnitude (1)magphot.mag;em.opt.IfloatnullableJmag? J-band magnitude (2)magphot.mag;em.IR.JfloatnullableHmag? H-band magnitude (2)magphot.mag;em.IR.HfloatnullableKmag? K-band magnitude (2)magphot.mag;em.IR.KfloatnullableE(B-V)? Reddening value (3)magphot.color.excessfloatnullable_RApositinos from 2MASS name (right ascension part)degpos.eq.ra;meta.main_DEpositinos from 2MASS name (declination part)degpos.eq.dec;meta.mainJ/MNRAS/481/373/table3Stellar parameters for each star in our M4 sampleTypeStar type (AGB : asymptotic giant branch star or RGB : red giant branch star)src.classcharTeffspSpectroscopic effective temperatures (1)Kphys.temperature.effectiveinte_TeffspError on Teffsp (1)Kstat.errorintloggSurface gravity (2)log(cm.s**-2)phys.gravityfloatvtMicroturbulence values (1)km/sstat.value;phys.veloc.microTurbfloate_vtError on vt (1)km/sstat.errorfloatTeffphEffective temperatures estimated from photometric colour-Teff relations used in the PHOBOS testKphys.temperatureintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTarget IDmeta.id;meta.maincharJ/MNRAS/481/373/table5Chemical abundances for each star in our M4 samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTarget IDmeta.id;meta.maincharTypeStar type (AGB : asymptotic giant branch star or RGB : red giant branch star)src.classcharloge(FeI)FeI abundance (1)phys.abundfloate_loge(FeI)Error on loge(FeI) (2)stat.errorfloatloge(FeII)FeII abundance (1)phys.abundfloate_loge(FeII)Error on loge(FeII) (2)stat.errorfloatloge(O)O abundance (1)phys.abundfloate_loge(O)Error on loge(O) (2)stat.errorfloatloge(Na)Na abundance (1)phys.abundfloate_loge(Na)Error on loge(Na) (2)stat.errorfloatloge(Mg)Mg abundance (1)phys.abundfloate_loge(Mg)Error on loge(Mg) (2)stat.errorfloatloge(Al)Al abundance (1)phys.abundfloate_loge(Al)Error on loge(Al) (2)stat.errorfloat