J/AJ/128/2402ivo://CDS.VizieR/J/AJ/128/2402doi:10.26093/cds/vizier.51282402CDSLai D.K.Bolte M.Johnson J.A.Lucatello S.2017-10-02T19:28:35Z2007-04-10T21:21:47ZCDS support team

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

cds-question@unistra.frpopulation-ii-starschemically-peculiar-starsWe present chemical abundances for 110 stars identified in objective-prism surveys as candidates for being very metal-poor. The abundances are derived from high-S/N, intermediate-resolution spectra obtained with the Keck Observatory Echellette Spectrograph and Imager (ESI). An additional 25 stars with well-determined abundances ranging from [Fe/H]=-1.5 to -3.2 were observed and the results used to help calibrate our analysis and determine the accuracy of our abundance determinations. Abundances for the program stars were measured for Fe, Mg, Ca, Ti, Cr, and Ba with an accuracy of approximately 0.3dex. Fifty-three of the stars in our sample have [Fe/H]<=-2, 22 have [Fe/H]<=-2.5, and 13 have [Fe/H]<=-2.9. Surprisingly, approximately one-third of the sample is relatively metal-rich, with [Fe/H]>-1.5. In addition to identifying a number of extremely metal-poor stars, this study also shows that moderate-resolution spectra obtained with the Keck ESI yield relatively accurate abundances for stars as faint as V=14 with modest exposure time (~20 minutes). This capability will prove useful if the so-far elusive stars at [Fe/H]<-4 turn out to be mostly fainter than V=15.2004AJ....128.2402Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/128/2402CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/90/2089 : Stars of very low metal abundance (Beers+, 1985)J/AJ/103/1987 : Stars of very low metal abundance (Beers+, 1992)J/ApJS/123/639 : UBV photometry of metal-weak candidates (Norris+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/128/2402https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/128/2402http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/128/2402https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/128/2402https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/128/2402http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/128/2402GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/128/2402/stars (Star positions (from Simbad))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/128/2402/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/128/2402/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/128/2402/stars?GETtext/xml+votable180.050000true134.792083-4.0269440.0055555555555555566/51 79 3712 4376 5012 5015 5246 6453 6497 6792 7710 7767 8200 8215 8244 8258 8264 8328 8367 8766 8864 9666 9912 10149 10173 10430 10476 10921 11543 12405 16666 16815 16854 16911 17174 17191 17221 17357 17420 17512 17566 17625 17642 17879 17994 18503 18683 18707 18718 18903 18942 18972 18973 18990 19304 19311 19478 19485 19566 19901 21269 23527 25276 25320 25929 25959 26111 26415 26418 26455 26457 26462 26577 26594 26608 26653 27142 27182 27270 27273 27709 27861 27946 27969 27989 28054 28097 28336 28540 28594 29490 31094 31270 31361 31363 31366 31368 31370 31372 31375 31384 31386 31394 31403 31585 32468 36295 36375 36379 36564 36628 36837 40399 40403 40434 40436 40441 40446 40772 40783 40801 40817 40825 40944 44903 44917 45021 45023 48501 48514 48555 48625 48734 48766https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/128/2402?format=asciiOpticaldefaultJ/AJ/128/2402/starsStar positions (from Simbad)SNameSimbad namemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharprimaryRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Simbad declination (J2000)pos.eq.dec;meta.mainSimbadSimbad column added by the CDScharJ/AJ/128/2402/table2Program star photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identificationmeta.id;meta.maincharf_Name[d*] Flag on Name (1)meta.codecharVmag? The V-band magnitudemagphot.mag;em.opt.VfloatnullableB-V? The (B-V) color indexmagphot.color;em.opt.B;em.opt.VfloatnullableE(B-V)? The (B-V) color excessmagphot.color.excessfloatnullableb-y? Stroemgren (b-y) colormagphot.color;em.opt.B;em.opt.Vfloatnullablec1? Stroemgren c1 indexmagphot.colorfloatnullable(b-y)0? Intrinsic Stroemgren (b-y) color indexmagphot.color;em.opt.B;em.opt.Vfloatnullable(c1)0? Intrinsic c1 indexmagphot.colorfloatnullabler_NameReference for Namemeta.bibintExpTimeExposure timetime.duration;obs.exposureintObs.DateDate of the observationtime.epochnullableJ/AJ/128/2402/ewEquivalent widths measurement of MgI, CaI, TiII, CrI, BaII and FeI (tables 3-6 of the paper)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identificationmeta.id;meta.maincharEW4167Mg? Mg I (4167.27) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5172Mg? Mg I (5172.69) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5183Mg? Mg I (5183.61) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5528Mg? Mg I (5528.41) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4425Ca? Ca I (4425.44) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5586Ca? Ca I (5586.76) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6122Ca? Ca I (6122.22) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6162Ca? Ca I (6162.18) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6439Ca? Ca I (6439.08) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6471Ca? Ca I (6471.66) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6717Ca? Ca I (6717.68) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4028Ti? Ti II (4028.34) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4395Ti? Ti II (4395.04) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4399Ti? Ti II (4399.77) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4443Ti? Ti II (4443.81) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4468Ti? Ti II (4468.50) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4563Ti? Ti II (4563.76) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4571Ti? Ti II (4571.98) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4589Ti? Ti II (4589.95) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW5336Ti? Ti II (5336.79) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW5345Cr? Cr I (5345.80) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4554Ba? Ba II (4554.04) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW6141Ba? Ba II (6141.75) equivalent width (1)1e-13mspect.line.eqWidthfloatnullableEW4045Fe? Fe I (4045.82) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4071Fe? Fe I (4071.74) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4383Fe? Fe I (4383.55) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4404Fe? Fe I (4404.76) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4442Fe? Fe I (4442.35) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW4919Fe? Fe I (4919.00) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5068Fe? Fe I (5068.77) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5074Fe? Fe I (5074.75) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5133Fe? Fe I (5133.69) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5216Fe? Fe I (5216.28) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5232Fe? Fe I (5232.95) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5302Fe? Fe I (5302.30) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5324Fe? Fe I (5324.19) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5383Fe? Fe I (5383.38) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5393Fe? Fe I (5393.17) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5405Fe? Fe I (5405.78) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5434Fe? Fe I (5434.53) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW5586Fe? Fe I (5586.77) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6065Fe? Fe I (6065.49) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6230Fe? Fe I (6230.73) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6252Fe? Fe I (6252.56) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6393Fe? Fe I (6393.61) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6411Fe? Fe I (6411.65) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6430Fe? Fe I (6430.85) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6609Fe? Fe I (6609.11) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6677Fe? Fe I (6677.99) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableEW6750Fe? Fe I (6750.15) equivalent width (1)1e-13mspect.line.eqWidth;em.opt.IfloatnullableJ/AJ/128/2402/table7Excitation potentials and oscillator strengthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonSpecies name and ionisation stagemeta.id;phys.atmol.ionStage;phys.atmol.ionizationcharLambdaWavelength in Angstroms0.1nmem.wlfloatlog(gf)Logarithm of the oscillator strengthphys.atmol.oscStrengthfloatExPotExcitation potentialeVphys.atmol.excitationfloatr_log(gf)Reference on log(gf)meta.bibintJ/AJ/128/2402/table8Program star atmospheres and radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identificationmeta.id;meta.maincharf_Name[d*] Flag on Name (1)meta.codecharTeff? Effective temperatureKphys.temperature.effectiveintnullablelog(g)? Logarithm of the surface gravitylog(cm.s**-2)phys.gravityfloatnullable[M/H]? Logarithm of the metallicitylog(Sun)phys.abund.FefloatnullableTeff0Reddening-corrected effective temperatureKphys.temperature.effectiveintlog(g)0Logarithm of the reddening-corrected surface gravitylog(cm.s**-2)phys.gravityfloat[M/H]0Logarithm of the reddening-corrected metallicitylog(Sun)phys.abund.FefloatRVRadial velocitykm/sphys.veloc;pos.heliocentricintJ/AJ/128/2402/table9Line InformationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identificationmeta.id;meta.maincharNFe? Number of Fe lines measuredmeta.numberintnullablesigmaFe? Standard deviation of Felog(Sun)stat.stdevfloatnullableNMg? Number of Mg linesmeta.numberintnullablesigmaMg? Standard deviation of Mglog(Sun)stat.stdevfloatnullableNCa? Number of Ca linesmeta.numberintnullablesigmaCa? Standard deviation of Calog(Sun)stat.stdevfloatnullableNTiII? Number of Ti II linesmeta.numberintnullablesigmaTiII? Standard deviation of Ti IIlog(Sun)stat.stdevfloatnullableNBaII? Number of Ba II linesmeta.numberintnullablesigmaBaII? Standard deviation of Ba IIlog(Sun)stat.stdevfloatnullableJ/AJ/128/2402/refsReferencesAutAuthors namemeta.bib.authorcharComCommentsmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintBibCodeBibCodemeta.bib.bibcodechar