J/ApJ/781/40ivo://CDS.VizieR/J/ApJ/781/40doi:10.26093/cds/vizier.17810040CDSPlacco V.M.Frebel A.Beers T.C.Christlieb N.Lee Y.S.Kennedy C.R.,Rossi S.Santucci R.M.2017-12-06T07:38:31Z2015-12-04T15:27:36ZCDS support team

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

cds-question@unistra.frhalo-starschemically-peculiar-starschemical-abundancesline-intensitiesWe report on the discovery of seven low-metallicity stars selected from the Hamburg/ESO Survey, six of which are extremely metal-poor (EMP, [Fe/H]{<=}-3.0), with four having [Fe/H]{<=}-3.5. Chemical abundances or upper limits are derived for these stars based on high-resolution (R~35000) Magellan/MIKE spectroscopy, and are in general agreement with those of other very and extremely metal-poor stars reported in the literature. Accurate metallicities and abundance patterns for stars in this metallicity range are of particular importance for studies of the shape of the metallicity distribution function of the Milky Way's halo system, in particular for probing the nature of its low-metallicity tail. In addition, taking into account suggested evolutionary mixing effects, we find that six of the program stars (with [Fe/H]{<=}-3.35) possess atmospheres that were likely originally enriched in carbon, relative to iron, during their main-sequence phases. These stars do not exhibit overabundances of their s-process elements, and hence may be, within the error bars, additional examples of the so-called CEMP-no class of objects.2014ApJ...781...40Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/781/40CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013)J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)J/ApJ/762/25 : The most metal-poor stars in HES and SDSS. I. (Norris+, 2013)J/AJ/142/188 : Metal-poor stars from the HES using CH G-band (Placco+, 2011)J/AJ/139/1051 : Carbon-enhanced metal-poor stars in the Galaxy (Placco+, 2010)J/A+A/484/721 : HES survey. IV. Candidate metal-poor stars (Christlieb+, 2008)J/ApJ/652/1585 : Bright metal-poor stars from HES survey (Frebel+, 2006)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/A+A/375/366 : Carbon stars from the Hamburg/ESO survey (Christlieb+ 2001)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/781/40https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/781/40http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/781/40https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/781/40https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/781/40http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/781/40GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/781/40/table3 (Derived stellar parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/781/40/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/781/40/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/781/40/table3?GETtext/xml+votable180.050000true12.68875-63.86388890.0055555555555555566/17095 33464 35695 45406 46311 46796 46813https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/781/40?format=asciidefaultJ/ApJ/781/40/table4Abundances for individual speciesIonIon designationphys.atmol.ionStagecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHEStar name in Hamburg/ESO survey (HHMM-DDMM)meta.id;meta.maincharprimarylog(e)? Log number abundance (log {epsilon})phys.abundfloatnullablel_[X/Fe][<] Upper limit flag on [X/Fe]meta.code.error;phys.abundchar[X/Fe]? Derived elemental abundance ratio (1)log(Sun)phys.abund;arith.ratiofloatnullablef_[X/Fe][a] Indicates [FeI/H] and [FeII/H] valuesmeta.codecharsigma? Standard error of the mean ({sigma})log(Sun)stat.errorfloatnullableN? NUmber of linesmeta.numberintnullableJ/ApJ/781/40/table3Derived stellar parameterse_VtUncertainty in Vt (2)km/sstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHEStar name in Hamburg/ESO survey (HHMM-DDMM)meta.id;meta.maincharprimaryTeff1Effective temperature (1)Kphys.temperature.effectiveinte_Teff1Uncertainty in Teff (1)Kstat.errorintlogg1Log of surface gravity (1)log(cm.s**-2)phys.gravityfloate_logg1Uncertainty in logg (1)log(cm.s**-2)stat.errorfloat[Fe/H]1Metallicity (1)log(Sun)phys.abund.Zfloate_[Fe/H]1Metallicity (1)log(Sun)stat.error;phys.abund.FefloatTeff2Effective temperature (2)Kphys.temperature.effectiveinte_Teff2Uncertainty in Teff2 (2)Kstat.errorintlogg2Log of surface gravity (2)log(cm.s**-2)phys.gravityfloate_logg2Uncertainty in logg2 (2)log(cm.s**-2)stat.errorfloatVtMicroturbulent velocity {ksi} (2)km/sphys.velocfloat[Fe/H]2Metallicity (2)log(Sun)phys.abund.Zfloate_[Fe/H]2Metallicity (2)log(Sun)stat.error;phys.abund.FefloatEWSimbad column added by the CDSmeta.ref.urlcharAbdSimbad column added by the CDSmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPosition from SIMBAD database (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD database (declination part)degpos.eq.dec;meta.mainJ/ApJ/781/40/table2Equivalent-width measurementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonIon designationphys.atmol.ionStagecharlambdaWavelength {lambda} (in {AA})0.1nmem.wlfloatEP? Excitation potential {chi}eVphys.atmol.excitationfloatnullableloggf? Log of the oscillation strengthphys.atmol.collStrengthfloatnullableEW0048? Equivalent width in HE 0048-6408 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW0048[sa] Flag on EW0048 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd0048? Log number abundance in HE 0048-6408 (log {epsilon})phys.abundfloatnullableEW0139? Equivalent width in HE 0139-2826 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW0139[sa] Flag on EW0139 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd0139? Log number abundance in HE 0139-2826 (log {epsilon})phys.abundfloatnullableEW2141? Equivalent width in HE 2141-3741 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW2141[sa] Flag on EW2141 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd2141? Log number abundance in HE 2141-3741 (log {epsilon})phys.abundfloatnullableEW2157? Equivalent width in HE 2157-3404 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW2157[sa] Flag on EW2157 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd2157? Log number abundance in HE 2157-3404 (log {epsilon})phys.abundfloatnullableEW2233? Equivalent width in HE 2233-4724 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW2233[sa] Flag on EW2233 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd2233? Log number abundance in HE 2233-4724 (log {epsilon)}phys.abundfloatnullablef_Abd2233[a] Flag on Abd2233 (a=upper limit; s=derived from spectral synthesis)meta.codecharEW2318? Equivalent width in HE 2318-1621 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW2318[sa] Flag on EW2318 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd2318? Log number abundance in HE 2318-1621 (log {epsilon})phys.abundfloatnullableEW2323? Equivalent width in HE 2323-6549 (in m{AA})0.1pmspect.line.eqWidthfloatnullablef_EW2323[sa] Flag on EW2323 (a=upper limit; s=derived from spectral synthesis)meta.codecharAbd2323? Log number abundance in HE 2323-6549 (log {epsilon})phys.abundfloatnullable