J/A+A/561/A94ivo://CDS.VizieR/J/A+A/561/A94doi:10.26093/cds/vizier.35610094CDSDonati P.Gaudin CantatBragaglia A.Friel E.Magrini L.,Smiljanic R.Vallenari A.Tosi M.Sordo R.Tautvaisiene G.,Blanco-Cuaresma S.Costado M.T.Geisler D.Klutsch A.Mowlavi N.,Munoz C.San Roman I.Zaggia S.Gilmore G.Randich S.Bensby T.,Flaccomio E.Koposov S.E.Korn A.J.Pancino E.Recio-Blanco A.,Franciosini E.de Laverny P.Lewis J.Morbidelli L.Prisinzano L.,Sacco G.Worley C.C.Hourihane A.Jofre P.Lardo C.Maiorca E.2017-10-13T15:42:05Z2014-01-10T13:24:03ZCDS support team

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

cds-question@unistra.fropen-star-clustersvisible-astronomybroad-band-photometryradial-velocityTrumpler 20 is an old open cluster (OC) located toward the Galactic centre, at about 3kpc from the Sun and ~7kpc from the Galactic centre. Its position makes this cluster particularly interesting in the framework of the chemical properties of the Galactic disc because very few old OCs reside in the inner part of the disc. For this reason it has been selected as a cluster target of the Gaia-ESO Survey, and spectra of many stars in the main sequence and red clump phases are now available. Moreover, although it has been studied by several authors in the past, no consensus on the evolutionary status of Tr 20 has been reached. The heavy contamination of field stars (the line of sight of Tr 20 crosses the Carina spiral arm) complicates the correct interpretation. Another interesting aspect of the cluster is that it shows a broadened main sequence turn-off and a prominent and extended red clump, characteristics that are not easily explained by classical evolutionary models. Exploiting both spectroscopic information from the Gaia-ESO Survey (and the ESO archive) and literature photometry, we obtain a detailed and accurate analysis of the properties of the cluster. We make use of the first accurate metallicity measurement ever obtained from several spectra of red clump stars, and of cluster membership determination using radial velocities. According to the evolutionary models adopted, we find that Tr 20 has an age in the range 1.35-1.66Gyr, an average reddening E(B-V) in the range 0.31-0.35mag, a distance modulus (m-M)_0_ between 12.64 and 12.72mag. The spectroscopic metallicity is [Fe/H]=+0.17dex. We discuss the structural properties of the object and constrain possible hypotheses for its broadened upper main sequence, by estimating the effect of differential reddening, and its extended red clump.2014A&A...561A..94Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/561/A94CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/391/1482 : BVIc photometry of Trumpler 20 (Platais+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/561/A94https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/561/A94http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/561/A94https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/561/A94https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/561/A94http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/561/A94GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/561/A94/catalog (BVI photometry and differential reddening (DR) corrections)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/561/A94/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/561/A94/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/561/A94/catalog?GETtext/xml+votable180.050000true189.927025-60.599913610.005555555555555556Cone search capability for table J/A+A/561/A94/table3 (Radial velocity table of GES targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/561/A94/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/561/A94/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/561/A94/table3?GETtext/xml+votable180.050000true189.6245475-60.659206670.0055555555555555566/430343.322582951404819e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/561/A94?format=asciiOpticaldefaultJ/A+A/561/A94/catalogBVI photometry and differential reddening (DR) correctionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/14193]+ Identification indexspect.index;meta.mainintprimaryindexedidC10[1/15617]? Identification index of C10 catalogue (Carraro et al., 2010AJ....140..954C)meta.idintnullableidP08[1/7202]?=99999 Identification index of P08 catalogue (Platais et al. 2008, J/MNRAS/391/1482 <Cl* Trumpler 20 PMF NNNN> in Simbadmeta.idintnullableDistDistance from the cluster centrearcminpos.angDistancedoubleVNumber of stars with velocity measured in table3 within 1arcsecmeta.numberintnullableRAJ2000Right Ascension coordinate J2000degpos.eq.ra;meta.mainDEJ2000Declination coordinate J2000degpos.eq.dec;meta.mainVmag1? V magnitude from C10 cataloguemagphot.mag;em.opt.Vfloatnullable(B-V)1? B-V colour index from C10 cataloguemagphot.color;em.opt.B;em.opt.Vfloatnullable(V-I)1? V-I colour index from C10 cataloguemagphot.color;em.opt.V;em.opt.Ifloatnullable(U-V)1? U-V colour index from C10 cataloguemagphot.color;em.opt.U;em.opt.VfloatnullableVmag2? V magnitude from P08 cataloguemagphot.mag;em.opt.Vfloatnullable(B-V)2? B-V colour index from P08 cataloguemagphot.color;em.opt.B;em.opt.Vfloatnullable(V-I)2? V-I colour index from P08 cataloguemagphot.color;em.opt.V;em.opt.IfloatnullableE(B-V)? Differential reddening (DR) correction in E(B-V)magphot.color.excessfloatnullableVmag1c? Vmag1 (from C10) corrected for DRmagphot.mag;em.opt.Vfloatnullable(B-V)1c? (B-V)1 (from C10) corrected for DRmagphot.color;em.opt.B;em.opt.VfloatnullableJ/A+A/561/A94/table3Radial velocity table of GES targetsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintidC10[1/15617]? Identification index of C10 catalogue (Carraro et al., 2010AJ....140..954C)meta.idintnullableidP08[1/7202]? Identification index of P08 catalogue (Platais et al. 2008, J/MNRAS/391/1482), <Cl* Trumpler 20 PMF NNNN> in Simbadmeta.idintnullableidGESIdentification index of the Gaia-ESO Survey (HHMMSSss+DDMMSSs, ICRS)meta.id;meta.maincharVmagV magnitude from C10 or P08magphot.mag;em.opt.VfloatBmagB magnitude from C10 or P08magphot.mag;em.opt.BfloatRAJ2000Right Ascension coordinate J2000degpos.eq.ra;meta.mainDEJ2000Declination coordinate J2000degpos.eq.dec;meta.mainRV1? Radial velocity from Giraffe-HR09b spectra (514.3-535.6nm)km/sspect.dopplerVelocfloatnullablee_RV1? Error on RV2km/sstat.errorfloatnullableRV2? Radial velocity from Giraffe-HR15n spectra (476-684nm)km/sspect.dopplerVelocfloatnullablee_RV2? Error on RV2km/sstat.errorfloatnullableRV3? Radial velocity from UVES spectra (647-679nm)km/sspect.dopplerVelocfloatnullablee_RV3? Error on RV3km/sstat.errorfloatnullablePhNumber of stars with photometry within 1arcsecmeta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar