J/ApJ/833/20ivo://CDS.VizieR/J/ApJ/833/20doi:10.26093/cds/vizier.18330020CDSYoon J.Beers T.C.Placco V.M.Rasmussen K.C.Carollo D.He S.,Hansen T.T.Roederer I.U.Zeanah J.2018-07-04T07:17:12Z2017-04-19T08:31:22ZCDS support team

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

cds-question@unistra.frchemical-abundanceschemically-peculiar-starscarbon-starsWe investigate anew the distribution of absolute carbon abundance, A(C)=log{epsilon}(C), for carbon-enhanced metal-poor (CEMP) stars in the halo of the Milky Way, based on high-resolution spectroscopic data for a total sample of 305 CEMP stars. The sample includes 147 CEMP-s (and CEMP-r/s) stars, 127 CEMP-no stars, and 31 CEMP stars that are unclassified, based on the currently employed [Ba/Fe] criterion. We confirm previous claims that the distribution of A(C) for CEMP stars is (at least) bimodal, with newly determined peaks centered on A(C)=7.96 (the high-C region) and A(C)=6.28 (the low-C region). A very high fraction of CEMP-s (and CEMP-r/s) stars belongs to the high-C region, while the great majority of CEMP-no stars resides in the low-C region. However, there exists complexity in the morphology of the A(C)-[Fe/H] space for the CEMP-no stars, a first indication that more than one class of first-generation stellar progenitors may be required to account for their observed abundances. The two groups of CEMP-no stars we identify exhibit clearly different locations in the A(Na)-A(C) and A(Mg)-A(C) spaces, also suggesting multiple progenitors. The clear distinction in A(C) between the CEMP-s (and CEMP-r/s) stars and the CEMP-no stars appears to be as successful, and likely more astrophysically fundamental, for the separation of these sub-classes as the previously recommended criterion based on [Ba/Fe] (and [Ba/Eu]) abundance ratios. This result opens the window for its application to present and future large-scale low- and medium-resolution spectroscopic surveys.2016ApJ...833...20Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/833/20CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/824/L19 : BD+44493 CEMP star equivalent widths (Roederer+, 2016)J/A+A/586/A158 : Binary properties of CH and CEMP stars (Jorissen+, 2016)J/ApJ/814/121 : CASH project. III. The CEMP star HE0414-0343 (Hollek+, 2015)J/ApJ/812/109 : HST+Keck spectroscopy of bright CEMP-s stars (Placco+, 2015)J/A+A/581/A22 : 67 CEMP-s stars model analysis (Abate+, 2015)J/ApJ/807/171 : SkyMapper Survey metal-poor star spectrosc. (Jacobson+, 2015)J/A+A/579/A28 : Abundances of 3 CEMP stars (Bonifacio+, 2015)J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)J/ApJ/781/40 : Metal-poor stars from HES survey. II. (Placco+, 2014)J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/ApJ/773/33 : The metal-poor subgiant BD+44 493 chemical data (Ito+, 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/145/13 : Metal-poor stars from SDSS/SEGUE. I. Abundances (Aoki+, 2013)J/A+A/548/A34 : Abundances od Carbon-enhanced metal-poor stars (Allen+, 2012)J/MNRAS/418/284 : s-process in low-metallicity stars. II. (Bisterzo+, 2011)J/ApJ/742/54 : CASH project II. extremely metal-poor stars (Hollek+, 2011)J/MNRAS/412/843 : SAGA extremely metal-poor stars (Suda+, 2011)J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)J/MNRAS/404/253 : Heavy element abundances in HD 209621 (Goswami+, 2010)J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)J/A+A/490/769 : Yields from extremely metal-poor stars (Campbell+, 2008)J/ApJ/679/1549 : Spectrosc. of metal-poor star CS17435-00532 (Roederer+, 2008)J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/ApJ/617/1091 : La and Eu abundances in 85 stars (Simmerer+, 2004)J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)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)http://sagadatabase.jp/ : SAGA -Stellar Abundances for Galactic Archeologyhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/833/20https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/833/20http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/833/20https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/833/20https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/833/20http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/833/20GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/833/20/table1 (Literature data and classifications for Carbon-Enhanced Metal-Poor (CEMP) stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/833/20/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/833/20/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/833/20/table1?GETtext/xml+votable180.050000true139.70799055637.7407811670.0055555555555555566/25 2067 2426 4098 4854 5768 5775 6375 6917 7456 7787 8127 8197 8201 8314 9291 9581 10147 10165 10209 10430 10682 12658 12880 13087 15349 16365 16501 16654 16659 16671 16679 16680 16763 16795 16814 16819 16880 16922 16935 17040 17095 17101 17174 17221 17233 17256 17380 17381 17392 17398 17411 17432 17451 17545 17623 17635 17679 17730 17793 17858 17986 17994 18098 18226 18483 18507 18545 18566 18636 18653 18663 18683 18691 18707 18708 18719 18737 18973 19000 19010 19017 19023 19073 19923 19968 20330 21016 21195 22406 22541 22625 22632 22650 22719 22766 23180 23199 23220 23240 23304 23467 24905 24914 24918 24975 25030 25116 25357 25470 25549 25551 25574 25575 25595 25677 25693 25733 25743 25785 25819 25832 25926 25928 25948 25950 25963 25993 26005 26019 26057 26115 26147 26166 26176 26183 26191 26200 26225 26232 26530 26645 26658 26829 26886 26944 26961 26995 27030 27048 27065 27091 27319 27322 27444 27589 27778 27898 28223 28251 28475 29001 29311 30041 30042 31136 31273 31394 31719 32553 32555 33185 33192 33515 33526 33670 33703 33708 33715 34008 34012 34037 34046 34069 34079 34425 34504 34589 34844 35009 35186 35367 35469 35543 35588 35599 35695 35752 35775 35801 35803 35881 35883 35889 35899 35992 36196 36228 36330 36426 36461 36503 36542 36548 36583 36628 36737 38399 38935 38953 40319 40404 42307 43365 43741 43938 44016 44268 44410 44575 44580 44607 44658 44671 44842 44870 44909 44939 44965 44990 45335 45345 45404 45406 45427 45463 45470 45494 45676 45790 45796 45806 45825 45837 45904 45913 46195 46282 46479 46508 46540 46565 46614 46662 46663 46704 46720 46780 46796 46801 46840 46848 46967 46973 47009 47018 47193 47217 47344 47436 47478 47518 47519 47541 47556 47869 48173 48234 48392 48415 48481 48511 48555 48577 48614 48628 48722 48798 48862 49078https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/833/20?format=asciidefaultJ/ApJ/833/20/table1Literature data and classifications for Carbon-Enhanced Metal-Poor (CEMP) starsSimbadNameSimbad column added by the CDSmeta.idcharA(C)[5/9.4] Absolute Carbon abundance = log{epsilon}Cphys.abundfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupObject group (G1)src.classcharNameIdentifier (1)meta.id;meta.maincharprimaryf_NameFlag on Name (2)meta.codecharADisplay Na and Mg abundances for the Group II and III CEMP-no starsmeta.ref.urlcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainTeff[3500/7000] Effective temperatureKphys.temperature.effectiveintlog(g)[0.1/5.1] Log surface gravitylog(cm.s**-2)phys.gravityfloatl_[Fe/H]Limit flag on [Fe/H]meta.code.error;phys.abund.Fechar[Fe/H][-8/3.1] Metallicitylog(Sun)phys.abund.Zfloatl_[C/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[C/Fe][-0.01/5.4] Log C/Fe abundance ratio relative Sunlog(Sun)phys.abundfloatl_[C/Fe]cLimit flag on [C/Fe]cmeta.code.error;phys.abundchar[C/Fe]c[0.6/5.4] Corrected Log C/Fe abundance ratiolog(Sun)phys.abundfloatl_A(C)Limit flag on A(C)meta.code.errorcharl_[Ba/Fe]Limit flag on [Ba/Fe]meta.code.error;phys.abundchar[Ba/Fe][-3/3.5]? Log Ba/Fe I Abundance ratio relative to Sunlog(Sun)phys.abundfloatnullablef_[Ba/Fe]Flag on [Ba/Fe] (3)meta.codecharl_[Eu/Fe]Limit flag on [Eu/Fe]meta.code.error;phys.abundchar[Eu/Fe][-0.5/4.5]? Log Eu/Fe I Abundance ratio relative to Sunlog(Sun)phys.abundfloatnullablef_[Eu/Fe]Flag on [Eu/Fe] (3)meta.codecharClassClassification (Ba|A(C)) (4)src.classcharBinBinarity status code (5)meta.codecharf_BinFlag on Bin (6)meta.codecharOut[x] Interesting outlier flag (7)meta.codecharAuthFirst author and year of the referencemeta.bib.authorcharBibcodeADS/SIMBAD bibcode of the referencemeta.bib.bibcodecharCCatDisplay data within 2" from Barklem+, 2005, J/A+A/439/129; Aoki+, 2013, J/AJ/145/13; Yong+, 2013, J/ApJ/762/26; Cohen+, 2013, J/ApJ/778/56; Roederer+, 2014, J/AJ/147/136 and Jacobson+, 2015, J/ApJ/807/171meta.ref.urlintnullableJ/ApJ/833/20/table2Na and Mg abundances for the Group II and Group III CEMP-no starsl_[Na/Fe]Limit flag on [Na/Fe]meta.code.error;phys.abundcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupGroup type (G1)src.classcharNameStar designationmeta.id;meta.maincharl_[Fe/H]Limit flag on [Fe/H]meta.code.error;phys.abund.Fechar[Fe/H][-7.8/-2.6] Metallicitylog(Sun)phys.abund.ZfloatA(C)[5.2/7.3] Absolute Carbon abundance (1)phys.abundfloat[Na/Fe][-0.7/2.5]? Log Na/Fe Abundance ratiolog(Sun)phys.abundfloatnullablef_[Na/Fe][a] Flag on [Na/Fe] (2)meta.codecharl_A(Na)Limit flag on A(Na)meta.code.errorcharA(Na)[0.5/4.4]? Absolute Na abundance (3)phys.abundfloatnullablef_A(Na)[b] Flag on A(Na) (2)meta.codecharl_[Mg/Fe]Limit flag on [Mg/Fe]meta.code.error;phys.abundchar[Mg/Fe][-0.07/3.4] Log Mg/Fe Abundance ratiolog(Sun)phys.abundfloatf_[Mg/Fe][ac] Flag on [Mg/Fe] (2)meta.codecharl_A(Mg)Limit flag on A(Mg)meta.code.errorcharA(Mg)[2.4/5.7] Absolute Mg abundance (3)phys.abundfloatf_A(Mg)[b] Flag on A(Mg) (2)meta.codecharAuthFirst author and year of the referencemeta.bib.authorcharBibCodeADS/SIMBAD bibcode of the referencemeta.bib.bibcodechar