J/A+AS/86/209ivo://CDS.VizieR/J/A+AS/86/209CDSVazquez R.A.Feinstein A.2018-01-05T08:57:18Z2010-01-10T17:26:15ZCDS support team

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

cds-question@unistra.fropen-star-clustersinfrared-photometryvisible-astronomyWide-band photometryUBVRI photoelectric photometry was obtained in the field of the open cluster Tr 18. From the analysis of the data we confirm that several distant OB stars were wrongly assumed as cluster members in previous investigations. The true distance modulus is 10.95, equivalent to a distance of 1550pc with the adopted age of (9.0+/-1.0)x10^7^yr. The GH Car Cepheid variable is very much probably a cluster member in view of its spatial position and the average absolute magnitude. However, some arguments are given to suggest that the reality of this cluster is still an open question. The observations in the Cousins system were carried out during 9 nights in April 1989 at Cerro Tololo Interamerican Observatory, with a single channel photometer attaéched to the 60cm Lowell telescope. The positions and identifications with large astrometric surveys was achieved by B. Skiff (Lowell Obs.) in 2010.1990A&AS...86..209Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/86/209CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/86/209https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/86/209http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/86/209https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/86/209https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/86/209http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/86/209GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+AS/86/209/table1 (UBVRI photometry and positions of stars in the field of Tr 18)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+AS/86/209/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+AS/86/209/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+AS/86/209/table1?GETtext/xml+votable180.050000true167.717875-60.74166670.0055555555555555566/37926https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+AS/86/209?format=asciiOpticalInfrareddefaultJ/A+AS/86/209/table1UBVRI photometry and positions of stars in the field of Tr 18recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1,109] Sequential number of star in clustermeta.recordintRAJ2000Right Ascension J2000 (1)pos.eq.ra;meta.mainDEJ2000Declination J2000 (1)pos.eq.dec;meta.mains[UM] Reference of position: UCAC2 (I/289) (1) or 2MASS (II/246) (1)meta.ref;pos.framecharUCAC2? Number in UCAC2 catalog (I/289)meta.idintnullableVmagJohnson V magnitudemagphot.mag;em.opt.VfloatB-VJohnson (B-V) color indexmagphot.color;em.opt.B;em.opt.VfloatU-BJohnson (U-B) color indexmagphot.color;em.opt.U;em.opt.BfloatV-RCousins (V-R) color indexmagphot.color;em.opt.V;em.opt.RfloatV-ICousins (V-I) color indexmagphot.color;em.opt.V;em.opt.IfloatRemRemarks and cross-identifications (1)meta.notecharSimbadSimbad column added by the CDSchar