J/ApJ/735/L46ivo://CDS.VizieR/J/ApJ/735/L46doi:10.26093/cds/vizier.17359046CDSBensby T.Alves-Brito A.Oey M.S.Yong D.Melendez J.2017-09-29T09:02:45Z2013-01-22T17:13:00ZCDS support team

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

cds-question@unistra.frchemical-abundancesmilky-way-galaxyradial-velocitygiant-starsstellar-distancek-starsBased on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes, we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13kpc. The outer disk sample is complemented with samples of red giants from the inner Galactic disk and the solar neighborhood, analyzed using identical methods. For Galactocentric distances beyond 10kpc, we only find chemical patterns associated with the local thin disk, even for stars far above the Galactic plane. Our results show that the relative densities of the thick and thin disks are dramatically different from the solar neighborhood, and we therefore suggest that the radial scale length of the thick disk is much shorter than that of the thin disk. We make a first estimate of the thick disk scale length of L_thick_=2.0kpc, assuming L_thin_=3.8kpc for the thin disk. We suggest that radial migration may explain the lack of radial age, metallicity, and abundance gradients in the thick disk, possibly also explaining the link between the thick disk and the metal-poor bulge.2011ApJ...735L..46Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/735/L46CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/A+A/546/A57 : Structure and formation of the Bulge (Uttenthaler+, 2012)J/A+A/534/A136 : Halo red giants from the SEGUE survey (Martell+, 2011)J/A+A/513/A35 : Abundances of Galactic red giants (Alves-Brito+, 2010)J/A+A/512/A41 : Abundances of microlensed stars in the Bulge (Bensby+, 2010)J/A+A/465/799 : Abundances of Galactic Bulge red giants (Lecureur+, 2007)J/AJ/132/902 : Abundances of 54 Cepheids (Luck+, 2006)J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)J/AJ/130/1111 : Elemental abundances of field red giants (Carney+, 2005)J/A+A/413/159 : Galactic abundance gradient. V. (Andrievsky+, 2004)J/A+A/433/185 : Detailed abundance analysis of F and G dwarfs (Bensby+, 2005)J/A+A/415/155 : Oxygen abundances in the Galactic disk (Bensby+, 2004)J/A+A/410/527 : Abundances in the Galactic disk (Bensby+, 2003)J/AJ/109/1095 : Thick Disk Chemical Abundance Distribution (Gilmore+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/735/L46https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/735/L46http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/735/L46https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/735/L46https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/735/L46http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/735/L46GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/735/L46/table1 (Stellar parameters, kinematics, and abundances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/735/L46/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/735/L46/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/735/L46/table1?GETtext/xml+votable180.050000true68.62466673.10036110.0055555555555555566/22330 22414 22438 22623 22786 22792 22914 22942 22953 22981 23001 23004 23027 23303 23372 23382 23601 23717 25906 29053 29140 29719 29728 29735 29749 29831 29837 29868 29922 42011 42079 42100 42107 42135 42234 42568 42649 42672 42677 42696 42697 42721 44036 44041 44167 44175 44210 44234 44572 44608 44647 44649 44651 44781 44792 44810 45755 45796 47135 47147 48775 48782https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/735/L46?format=asciiOpticaldefaultJ/ApJ/735/L46/table1Stellar parameters, kinematics, and abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSThe 2MASS identification (HHMMSSss+DDMMSSs; J2000)meta.id;meta.maincharDist[859/12930] Distance from the Sunpcpos.distance;pos.heliocentricintHRVHeliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatULSR? U velocity relative to LSRkm/sphys.veloc;pos.cartesian.xintnullableVLSR? V velocity relative to LSRkm/sphys.veloc;pos.cartesian.yintnullableWLSR? W velocity relative to LSRkm/sphys.veloc;pos.cartesian.zintnullableTeff[3800/4600] Effective temperatureKphys.temperature.effectiveintlog(g)[0.1/2.4] Log of the surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]The [Fe/H] abundance ratio relative to the Sunlog(Sun)phys.abund.Fe;arith.ratiofloat[Mg/Fe]The [Mg/Fe] abundance ratio relative to the Sunlog(Sun)phys.abund;arith.ratiofloat[Si/Fe]? The [Si/Fe] abundance ratio relative to the Sunlog(Sun)phys.abund;arith.ratiofloatnullable[Ti/Fe]The [Ti/Fe] abundance ratio relative to the Sunlog(Sun)phys.abund;arith.ratiofloatSimbadSimbad column added by the CDSmeta.refchar_RAPositions from 2MASS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from 2MASS names (declination part)degpos.eq.dec;meta.main