J/ApJ/762/27ivo://CDS.VizieR/J/ApJ/762/27doi:10.26093/cds/vizier.17620027CDSYong D.Norris J.E.Bessell M.S.Christlieb N.Asplund M.Beers T.C.,Barklem P.S.Frebel A.Ryan S.G.2017-12-06T07:38:06Z2014-10-10T13:43:12ZCDS support team

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

cds-question@unistra.frmetallicityhalo-starschemically-peculiar-starseffective-temperatureWe examine the metallicity distribution function (MDF) and fraction of carbon-enhanced metal-poor (CEMP) stars in a sample that includes 86 stars with [Fe/H]<=-3.0, based on high-resolution, high signal-to-noise spectroscopy, of which some 32 objects lie below [Fe/H]=-3.5. After accounting for the completeness function, the "corrected" MDF does not exhibit the sudden drop at [Fe/H]=-3.6 that was found in recent samples of dwarfs and giants from the Hamburg/ESO survey. Rather, the MDF decreases smoothly down to [Fe/H]=-4.1. Similar results are obtained from the "raw" MDF. We find that the fraction of CEMP objects below [Fe/H]=-3.0 is 23%+/-6% and 32%+/-8% when adopting the Beers & Christlieb (2005ARA&A..43..531B) and Aoki et al. (2007, J/ApJ/655/492) CEMP definitions, respectively. The former value is in fair agreement with some previous measurements, which adopt the Beers & Christlieb criterion.2013ApJ...762...27Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/762/27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/ApJ/762/26 : Paper II. 190 Galactic halo stars (Yong+, 2013)J/ApJ/762/25 : Most metal-poor stars in HES and SDSS: Pap. I. (Norris+, 2013)J/A+A/501/519 : Extremely metal-poor stars abundances (Bonifacio+, 2009)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/ApJ/658/367 : Abundances of carbon stars in Galactic halo (Komiya+, 2007)J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)J/ApJ/652/1585 : Bright metal-poor stars from HES survey (Frebel+, 2006)J/AJ/132/137 : Abundances of extremely metal-poor carbon stars (Cohen+, 2006)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/AJ/117/981 : Estimation of stellar metal abundance. II. (Beers+, 1999)J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/762/27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/762/27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/762/27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/762/27https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/762/27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/762/27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/762/27/table1 (Stellar parameters and carbon abundance)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/762/27/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/762/27/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/762/27/table1?GETtext/xml+votable180.050000true7.2944792-19.16868060.0055555555555555566/2067 5406 5450 5723 8228 8328 8766 8864 10149 10173 10430 10921 16549 16654 16795 16935 17343 17392 17545 17578 17642 18719 19017 19210 19211 25357 25574 25678 25719 25813 25887 25891 26232 26658 26941 28054 28097 30891 31377 31394 31585 33579 33642 34069 34513 34574 34844 35009 35181 35524 35532 35561 35710 35731 35803 35825 36356 36542 36658 36705 36737 36789 36837 40319 40410 43926 44016 44575 45470 45797 45825 45913 45959 45969 46565 46699 46796 46958 47556 48234 48286 48501 48534 48734 48798 48862https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/762/27?format=asciiOpticaldefaultJ/ApJ/762/27/table1Stellar parameters and carbon abundanceSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharf_Name[de] Assumed gravity (1)meta.codecharRAJ20002MASS Hour of Right Ascension (J2000) (2)pos.eq.raDEJ20002MASS Degree of Declination (J2000) (2)pos.eq.decTeff[4558/6609] Effective temperatureKphys.temperature.effectiveintlog(g)[0.8/4.7] Log of the surface gravitylog(cm.s**-2)phys.gravityfloatxi[0.8/2.2] Turbulent velocity {xi}km/sphys.velocfloat[M/H]Model metallicitylog(Sun)phys.abund.Z;meta.modelledfloat[Fe/H][-5.8/-3] Derived metallicitylog(Sun)phys.abund.Zfloatl_[C/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[C/Fe][-0.7/4.3]? Log of the C/Fe abundance ratio (3)phys.abund;arith.ratiofloatnullableCrich[0/1] Carbon rich star? (0=C-normal) (4)meta.codeintRefSource reference code(s) (5)pos.framechar2MDisplay the 2MASS data within 2" (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RAPositions from SIMBAD database (right ascension part)degpos.eq.ra;meta.main_DEPositions from SIMBAD database (declination part)degpos.eq.dec;meta.main