J/ApJ/784/19ivo://CDS.VizieR/J/ApJ/784/19doi:10.26093/cds/vizier.17840019CDSCasey A.R.Keller S.C.Da Costa G.Frebel A.Maunder E.2017-09-04T08:00:33Z2017-07-03T13:39:57ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyhalo-starsline-intensitieschemical-abundancesWe present the first high-resolution spectroscopic study on the Orphan stream for five stream candidates, observed with the Magellan Inamori Kyocera Echelle spectrograph on the Magellan Clay telescope. The targets were selected from the low-resolution catalog of Casey et al. (2013ApJ...764...39C): three high-probability members, one medium, and one low-probability stream candidate were observed. Our analysis indicates that the low- and medium-probability targets are metal-rich field stars. The remaining three high-probability targets range over ~1 dex in metallicity, and are chemically distinct compared to the other two targets and all standard stars: low [{alpha}/Fe] abundance ratios are observed, and lower limits are ascertained for [Ba/Y], which sit well above the Milky Way trend. These chemical signatures demonstrate that the undiscovered parent system is unequivocally a dwarf spheroidal galaxy, consistent with dynamical constraints inferred from the stream width and arc. As such, we firmly exclude the proposed association between NGC 2419 and the Orphan stream. A wide range in metallicities adds to the similarities between the Orphan stream and Segue 1, although the low [{alpha}/Fe] abundance ratios in the Orphan stream are in tension with the high [{alpha}/Fe] values observed in Segue 1. Open questions remain before Segue 1 could possibly be claimed as the "parent" of the Orphan stream. The parent system could well remain undiscovered in the southern sky.2014ApJ...784...19Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/784/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/120/1841 : Abundances and Kinematics of Halo and Disk StarsJ/ApJ/698/865 : Halo streams in the SDSS-DR7 (Klement+, 2009)J/ApJ/711/573 : Detailed abundances in a halo stellar stream (Roederer+, 2010)J/ApJ/776/26 : RRab stars in the Orphan stream distances (Sesar+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/784/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/784/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/784/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/784/19https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/784/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/784/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/784/19/table1 (Observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/784/19/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/784/19/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/784/19/table1?GETtext/xml+votable180.050000true91.265417-32.9935560.0055555555555555566/20532 21269 26457 27044 27045 27047 31658 40716 41831 42496https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/784/19?format=asciidefaultJ/ApJ/784/19/table1ObservationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifier (HD NNNNNN, OSS-NN)meta.id;meta.maincharn_Name[LMH] Note on Name (1)meta.notecharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainVmag[5.86/17.82] V-band magnitude (2)magphot.mag;em.opt.VfloatDateUT Date of observationtime.epoch;obsnullableTimeUT Time of observationtime.epochnullableAirmass[1.01/2.0] Airmassobs.airMassfloatExpExposure timestime.duration;obs.exposurecharS/N[31/335] Signal-to-noise ratio (3)stat.snrintHV[-38.2/297.8] Heliocentric velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HV[0.9/1.3] Heliocentric velocity errorkm/sstat.errorfloatEWEquivalent width from table2meta.ref.urlcharerrorAbundance uncertainties in table6meta.ref.urlcharJ/ApJ/784/19/table2Equivalent Widths for Standard and Program StarsHD142948? HD 142948 equivalent width (1)1e-13mspect.line.eqWidthfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWaveWavelengthnmem.wldoubleSpecies[8.0/63.1] Species identifiermeta.id;meta.mainfloatchiExcitation potentialeVphys.atmol.excitationfloatlog(gf)Log of the oscillator strengthphys.atmol.oscStrengthfloatHD41667? HD 41667 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableHD44007? HD 44007 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableHD76932? HD 76932 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableHD136316? HD 136316 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableHD141531? HD 141531 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableOSS-3? OSS 3 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableOSS-6? OSS 6 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableOSS-8? OSS 8 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableOSS-14? OSS 14 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableOSS-18? OSS 18 equivalent width (1)1e-13mspect.line.eqWidthfloatnullableJ/ApJ/784/19/table6Abundance Uncertainties Due to Stellar ParametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifier (HD NNNNNN, OSS-NN)meta.id;meta.maincharSpeciesSpecies identifiermeta.idcharDATeffAbundance uncertainty from T_eff_stat.errorfloatDAloggAbundance uncertainty from log(g)stat.errorfloatDAvtAbundance uncertainty from microturbulencestat.errorfloatSEDrandAbundance random standard error about the meanstat.errorfloate_[X/H]Total [X/H] abundance uncertaintystat.errorfloate_[X/Fe]? Total [X/Fe] abundance uncertaintystat.errorfloatnullable