J/ApJ/883/84ivo://CDS.VizieR/J/ApJ/883/84doi:10.26093/cds/vizier.18830084CDSRoederer I.U.Gnedin O.Y.2021-09-16T10:48:26Z2021-03-23T13:14:36ZCDS support team

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

cds-question@unistra.frchemical-abundancesline-intensitiesvisible-astronomyspectroscopychemically-peculiar-starsradial-velocitysloan-photometryWe observe two metal-poor main-sequence stars that are members of the recently discovered Sylgr stellar stream. We present radial velocities, stellar parameters, and abundances for 13 elements derived from high-resolution optical spectra collected using the Magellan Inamori Kyocera Echelle spectrograph. The two stars have identical compositions (within 0.13 dex or 1.2{sigma}) among all elements detected. Both stars are very metal-poor ([Fe/H]=-2.92+/-0.06). Neither star is highly enhanced in C ([C/Fe]<+1.0). Both stars are enhanced in the {alpha} elements Mg, Si, and Ca ([{alpha}/Fe]=+0.32+/-0.06), and the ratios among Na, Al, and all Fe-group elements are typical for other stars in the halo and ultra-faint and dwarf spheroidal galaxies at this metallicity. Sr is mildly enhanced ([Sr/Fe]=+0.22+/-0.11), but Ba is not enhanced ([Ba/Fe]{<}-0.4), indicating that these stars do not contain high levels of neutron-capture elements. The Li abundances match those found in metal-poor unevolved field stars and globular clusters (GCs) (log{epsilon}(Li)=2.05+/-0.07), which implies that environment is not a dominant factor in determining the Li content of metal-poor stars. The chemical compositions of these two stars cannot distinguish whether the progenitor of the Sylgr stream was a dwarf galaxy or a GC. If the progenitor was a dwarf galaxy, the stream may originate from a dense region such as a nuclear star cluster. If the progenitor was a GC, it would be the most metal-poor GC known.2019ApJ...883...84Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/883/84CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/195 : Globular Clusters in the Milky Way (Harris, 1996)VII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/ApJ/612/447 : Draco 119 and HD 88609 equivalent widths (Fulbright+, 2004)J/A+A/435/373 : Broadening of Fe II lines by H collisions (Barklem+, 2005)J/A+A/442/961 : Lithium content of the Gal. Halo stars (Charbonnel+, 2005)J/AJ/130/873 : BQS objects in the SDSS DR3 area (Jester+, 2005)J/ApJ/645/613 : Abundances of HD 221170 (Ivans+, 2006)J/ApJ/667/1267 : CrI transition probabilities (Sobeck+, 2007)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/A+A/501/519 : Extremely metal-poor turnoff stars (Bonifacio+, 2009)J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)J/ApJ/701/1053 : Abundances of 8 stars in the Draco dSph (Cohen+, 2009)J/A+A/503/541 : Neutral Li in late-type stars (Lind+, 2009)J/A+A/503/545 : Equivalent widths of Li, Na, Fe, Ca in NGC6397 (Lind+, 2009)J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)J/ApJ/719/931 : Chemical evolution of the UMi dSph (Cohen+, 2010)J/ApJ/708/560 : Spectroscopy of UMa II and Coma Ber (Frebel+, 2010)J/ApJS/191/352 : Abundances in stars of MW dwarf satellites (Kirby+, 2010)J/A+A/519/L3 : Lithium content of {omega} Cen (Monaco+, 2010)J/ApJ/711/350 : Metal-poor giant Boo-1137 abundances (Norris+, 2010)J/ApJ/711/573 : Abundances in a halo stellar stream (Roederer+, 2010)J/A+A/522/A26 : Fe Abundances in metal-poor stars (Sbordone+ 2010)J/ApJ/740/60 : EWs for NGC2419 and NGC7099 RGB stars (Cohen+, 2011)J/ApJS/194/35 : Atomic transition probabilities of Mn (Den Hartog+, 2011)J/AJ/142/63 : Abundance of five stars in NGC 6397 (Koch+, 2011)J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)J/A+A/546/A90 : NLTE analysis of Sr lines (Bergemann+, 2012)J/AJ/144/168 : Spectroscopy of Scl 1019417 and UMi 20103 (Kirby+, 2012)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJ/750/76 : R-process peaks elements in HD 160617 (Roederer+, 2012)J/ApJ/751/102 : Equivalent widths of 9 RGB in Carina dSph (Venn+, 2012)J/ApJ/763/61 : Abundances of red giant members of BootesI (Gilmore+, 2013)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/MNRAS/435/3667 : Equivalent widths of 6 NGC5694 stars (Mucciarelli+, 2013)J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)J/A+A/561/A87 : FLAMES observations of Terzan 8 (Carretta+, 2014)J/ApJ/786/74 : EW measurements of 6 Segue 1 red giants (Frebel+, 2014)J/A+A/562/A146 : Chemical abundances of 8 metal-poor stars (Ishigaki+, 2014)J/A+A/565/A23 : Abundances of NGC5897 red giants (Koch+, 2014)J/MNRAS/440/2665 : SDSS J021933.13+200830.2 spectroscopy (Roederer+, 2014)J/AJ/147/136 : Stars of very low metal abundance. VI. 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(Baumgardt+, 2019)J/ApJ/870/83 : Abundances in UFD galaxies GruI & TriII (Ji+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/883/84https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/883/84http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/883/84https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/883/84https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/883/84http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/883/84GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/883/84/table1 (Radial velocities, photometry, calculated Teff values, and adopted model atmosphere parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/883/84/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/883/84/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/883/84/table1?GETtext/xml+votable180.050000true180.5871269-0.34415110.0055555555555555566/26281-262822.367228618189496e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/883/84?format=asciiOpticaldefaultJ/ApJ/883/84/table1Radial velocities, photometry, calculated Teff values, and adopted model atmosphere parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS identifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharprimaryHRV[-209.5/-203.3] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HRV[0.7/0.7] HRV uncertaintykm/sstat.errorfloatumag[18.44/18.63] SDSS u-band (AB) magnitudemagphot.mag;em.opt.Ufloate_umag[0.01/0.02] Uncertainty on the umagmagstat.error;phot.magfloatgmag[17.56/17.77] SDSS g-band (AB) magnitudemagphot.mag;em.opt.Bfloate_gmag[0.01/0.01] Uncertainty on the gmagmagstat.error;phot.magfloatrmag[17.33/17.55] SDSS r-band (AB) magnitudemagphot.mag;em.opt.Rfloate_rmag[0.01/0.01] Uncertainty on the rmagmagstat.error;phot.magfloatimag[17.23/17.45] SDSS i-band (AB) magnitudemagphot.mag;em.opt.Ifloate_imag[0.01/0.01] Uncertainty on the imagmagstat.error;phot.magfloatBmag[17.89/18.09] Johnson B magnitude (1)magphot.mag;em.opt.Bfloate_Bmag[0.02/0.02] Uncertainty on the Bmagmagstat.error;phot.magfloatVmag[17.45/17.67] Johnson V magnitude (1)magphot.mag;em.opt.Vfloate_Vmag[0.01/0.01] Uncertainty on the Vmagmagstat.error;phot.magfloatRcmag[17.19/17.41] Cousins R magnitude (1)magphot.mag;em.opt.Rfloate_Rcmag[0.01/0.01] Uncertainty on the Rcmagmagstat.error;phot.magfloatIcmag[16.82/17.04] Cousins I magnitude (1)magphot.mag;em.opt.Ifloate_Icmag[0.01/0.01] Uncertainty on the Icmagmagstat.error;phot.magfloatE(B-V)[0.02/0.022] Reddening E(B-V)magphot.color.excessfloate_E(B-V)[0.01/0.01] E(B-V) uncertaintymagstat.errorfloatTeff(BV)[6206/6255] Effective temperature from B-VKphys.temperature.effectiveinte_Teff(BV)[140/142] Teff(BV) uncertaintyKstat.errorintTeff(VR)[6200/6613] Effective temperature from V-RcKphys.temperature.effectiveinte_Teff(VR)[83/202] Teff(VR) uncertaintyKstat.errorintTeff(VI)[6128/6556] Effective temperature from V-IcKphys.temperature.effectiveinte_Teff(VI)[108/198] Teff(VI) uncertaintyKstat.errorintTeff[6092/6242] Adopted effective temperatureKphys.temperature.effectiveinte_Teff[84/107] Teff uncertaintyKstat.error;phys.temperature.effectiveintlogg[4.46/4.47] Adopted log of surface gravitylog(cm.s**-2)phys.gravityfloate_logg[0.2/0.2] Logg uncertaintylog(cm.s**-2)stat.errorfloatVt[1.15/1.15] Adopted microturbulent velocitykm/sphys.velocfloate_Vt[0.1/0.1] Vt uncertaintykm/sstat.errorfloat[M/H][-3/-3] Adopted [M/H]log(Sun)phys.abund.Zfloate_[M/H][0.1/0.1] [M/H] uncertaintylog(Sun)stat.error;phys.abundfloatEWsDislay the Equivalent Widths from Table 2meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/883/84/table2Line listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonSpecies identifierphys.atmol.ionStagecharlambda[3502.28/7771.94] Wavelength in Angstroms0.1nmem.wlfloatExPot[0/9.15] Excitation potentialeVphys.atmol.excitationfloatlog(gf)[-3.21/0.51] Log of degeneracy times oscillator strengthphys.atmol.oscStrengthfloatr_log(gf)[1/15] Reference for log(gf) (1)meta.ref;pos.frameintEW1[7/134.7]? Equivalent width for J1202-0020 in milli-Angstroms1e-13mspect.line.eqWidthfloatnullablel_log(e1)Limit flag on log(e1)meta.code.errorcharlog(e1)[-1.2/7.5]? Log epsilon (LTE) abundance for J1202-0020phys.abund;arith.zpfloatnullableEW2[6.2/121]? Equivalent width for J1208+0024 in milli-Angstroms1e-13mspect.line.eqWidthfloatnullablel_log(e2)Limit flag on log(e2)meta.code.errorcharlog(e2)[-1.1/7.3]? Log epsilon (LTE) abundance for J1208+0024phys.abund;arith.zpfloatnullable