J/AJ/125/197ivo://CDS.VizieR/J/AJ/125/197doi:10.26093/cds/vizier.51250197CDSHarbeck D.Smith G.H.Grebel E.K.2023-04-06T16:50:54Z2004-10-17T11:40:36ZCDS support team

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

cds-question@unistra.frglobular-star-clustersvisible-astronomyWide-band photometrychemically-peculiar-starsWe report on a deep spectroscopic survey for star-to-star CN variations along the main sequence (MS) of the globular cluster 47 Tuc with ESO's Very Large Telescope. We find a significant bimodal distribution in the S(3839) index for main-sequence stars in the mass range ~0.85 to 0.65M_{sun}_, or from the main-sequence turnoff down to ~2.5 mag below the main-sequence turnoff. An anticorrelation of CN and CH is evident on the MS. The result is discussed in the context of the ability of faint MS stars to alter their surface composition through internal evolutionary effects. We argue against internal stellar evolution as the only origin for the abundance spread in 47 Tuc; an external origin such as pollution seems to be more likely.2003AJ....125..197Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/125/197CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/PASP/99/739 : BV photometry in 4 fields of 47 Tuc (Hesser+, 1987)J/A+AS/106/161 : (V,I) photometry in NGC 6356 and 47 Tuc (Bica+ 1994)J/AJ/127/1588 : 47 Tuc main-sequence star abundances (Briley+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/125/197https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/125/197http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/125/197https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/125/197https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/125/197http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/125/197GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/125/197/table1 (Data for Program Stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/125/197/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/125/197/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/125/197/table1?GETtext/xml+votable180.050000true6.5230833-71.97513890.0055555555555555566/33321https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/125/197?format=asciiOpticaldefaultJ/AJ/125/197/table1Data for Program StarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHSGStellar identification number, Cl* NGC 104 HSG NNNN in Simbadmeta.id;meta.mainintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainVmagJohnson V-band magnitudemagphot.mag;em.opt.VfloatB-VJohnson B-V colormagphot.color;em.opt.B;em.opt.VfloatS3839The {delta}S(3839) spectral index (1)magphot.colorfloatS4300The {delta}S(4300) spectral index (1)magphot.colorfloatCH4300The CH(4300) spectral index (1)magphot.colorfloatHKThe HK spectral index (1)magphot.colorfloatQflg[0/2] Quality flag, 0=reliable (2)meta.code.qualint