J/AJ/100/1191ivo://CDS.VizieR/J/AJ/100/1191doi:10.26093/cds/vizier.51001191CDSMorrison H.L.Flynn C.Freeman K.C.2023-04-06T16:47:09Z2012-03-17T06:19:42ZCDS support team

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

cds-question@unistra.frgiant-starsvisible-astronomyddo-photometryA sample of G and K giants approximately 4kpc from the Sun, covering the abundance range from solar to extreme halo has been selected without kinematic bias in a field aligned to measure galactic rotation. Accurate abundances, distances, and radial velocities have been measured. This sample has been combined with nonkinematically selected solar neighborhood objects taken from the literature, in order to examine the kinematics of the transition from disk to "thick disk" to halo. The metal-rich objects in the sample, with 0>[Fe/H]>-0.8, rotate rapidly around the galactic center and have low azimuthal velocity dispersion, {sigma}_{phi}_=40+/-10km/s. For objects in the range -0.5>[Fe/H]>-0.8, we find a small value for the asymmetric drift of 35+/-10km/s. We associate these objects with the thick disk, confirming the kinematical results of Ratnatunga and Freeman (1989, Cat.<V/65>) and others. In the abundance range -1.0>[Fe/H]>=-1.6 we find, in addition to objects with normal halo kinematics, objects in a disk configuration, confirming the results of Norris, Bessell, and Pickles (1985ApJS...58..463N). This disk is rotating rapidly, V_rot_=170+/-15km/s, and has a scale height of 1.4+/-0.7kpc, these kinematical and spatial properties are similar to those of the thick disk. We show that these objects have different kinematics from that of the globular clusters and a sample of local RR Lyraes in the same abundance range. This suggests to us that these objects are better associated with the thick disk than the halo, and we refer to them as "metal-weak thick-disk stars". Hence we suggest that the conventional chemical description of the thick disk (Gilmore and Wyse, 1985AJ.....90.2015G) be widened to include stars with abundances as low as [Fe/H]=-1.6. At the galactic plane, the density of these metal-weak thick-disk stars is similar to that of halo stars, so they significantly affect the measurement, from samples selected on abundance, of the components of the velocity ellipsoid for the halo in the solar neighborhood. For the halo giants in our sample we measure {sigma}_{phi}_=102+/-24 and V_rot_=17+/-24km/s. The rotation velocity and velocity ellipsoid for the metal-weak halo in the solar neighborhood have been rederived for objects with [Fe/H]<=-1.6 from the large sample of Norris (1986ApJS...61..667N), thus removing the possibility of contamination by metal-weak thick-disk stars. We derive V_rot_=25+/-15km/s and ({sigma}_r_, {sigma}_{phi}_, {sigma}_{theta}_)=(133+/-8, 98+/-13, 94+/-6)km/s. These values are more consistent with other information about the shape of the halo. For a description of the DDO photometric system, see e.g. <GCPD/12>1990AJ....100.1191Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/100/1191CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/164 : Catalogue of DDO photometry 88 (Mermilliod+ 1989)II/80 : Catalogue of homogeneous DDO photometry of bright stars (McLure+ 1981)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/100/1191https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/100/1191http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/100/1191https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/100/1191https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/100/1191http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/100/1191GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/100/1191/table1 (DDO photometry of 169 K giant candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/100/1191/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/100/1191/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/100/1191/table1?GETtext/xml+votable180.050000true321.4600727.530990.0055555555555555565/3077 3089 4783 4794 6165 6/12305 12353 12355 19127 19170-19171 19182 24645-24647 24652-24653 24655 24657-24659 24664-24665 24669 24681 24779 24832-24834 24836 43735 43751 43756 43761 43769 43773-43775 43838 43905 43911-43912 43944-43945 439473.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/100/1191?format=asciiOpticaldefaultJ/AJ/100/1191/table1DDO photometry of 169 K giant candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintgSimbad column added by the CDSmeta.ref.urlchar[MFF90]Object designationmeta.id;meta.maincharprimaryLumLuminosity class derived from DDO photometrysrc.class.luminositycharRA1950Right ascension (1950)pos.eq.ra;meta.mainDE1950Declination (1950)pos.eq.dec;meta.mainC45-4845-48 DDO colour index ({sigma}=0.009)magphot.color;em.opt.B;em.opt.BfloatC42-4542-45 DDO colour index ({sigma}=0.013)magphot.color;em.opt.B;em.opt.BfloatC41-4241-42 DDO colour index ({sigma}=0.013)magphot.color;em.opt.B;em.opt.BfloatC38-4238-42 DDO colour index ({sigma}=0.017)magphot.color;em.opt.U;em.opt.BfloatNobsNumber of DDO measurementsmeta.numberint_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexedJ/AJ/100/1191/table2Spectroscopic results of the giantso_RV? number of RV measurementsmeta.numberintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[MFF90]Star designationmeta.id;meta.maincharVmagV magnitude (no reddening correction applied)magphot.mag;em.opt.Vfloato_VmagNumber of BV observationsmeta.numberintB-VB-V colour index (no reddening correction applied)magphot.color;em.opt.B;em.opt.VfloatRV? Radial velocity (single measurement mean error {sigma}=10km/s)km/sstat.error;spect.dopplerVeloc;pos.heliocentricintnullable[Fe/H]Metallicitylog(Sun)phys.abund.ZfloatVMAGAbsolute V magnitudemagphys.magAbs;em.opt.VfloatDistDistancepcpos.distance;pos.heliocentricint