J/AJ/163/252ivo://CDS.VizieR/J/AJ/163/252doi:10.26093/cds/vizier.51630252CDSReggiani H.Ji A.P.Schlaufman K.C.Frebel A.Necib L.Nelson T.,Hawkins K.Galarza J.Y.2022-10-18T14:21:15Z2022-10-07T07:43:04ZCDS support team

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

cds-question@unistra.frhigh-velocity-starspopulation-ii-starschemical-abundancesvisible-astronomyspectroscopyLittle is known about the origin of the fastest stars in the Galaxy. Our understanding of the chemical evolution history of the Milky Way and surrounding dwarf galaxies allows us to use the chemical composition of a star to investigate its origin and to say whether it was formed in situ or was accreted. However, the fastest stars, the hypervelocity stars, are young and massive and their chemical composition has not yet been analyzed. Though it is difficult to analyze the chemical composition of a massive young star, we are well versed in the analysis of late-type stars. We have used high-resolution ARCES/3.5m Apache Point Observatory, MIKE/Magellan spectra to study the chemical details of 15 late-type hypervelocity star candidates. With Gaia EDR3 astrometry and spectroscopically determined radial velocities we found total velocities with a range of 274-520km/s and mean value of 381km/s. Therefore, our sample stars are not fast enough to be classified as hypervelocity stars, and are what is known as extreme-velocity stars. Our sample has a wide iron abundance range of -2.5<~[Fe/H]<~-0.9. Their chemistry indicates that at least 50% of them are accreted extragalactic stars, with iron-peak elements consistent with prior enrichment by sub- Chandrasekhar mass Type Ia supernovae. Without indication of binary companions, their chemical abundances and orbital parameters indicate that they are the accelerated tidal debris of disrupted dwarf galaxies.2022AJ....163..252Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/163/252CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)III/279 : RAVE 5th data release (Kunder+, 2017)I/345 : Gaia DR2 (Gaia Collaboration, 2018)II/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)J/ApJS/182/80 : Rare earth abundances (Sneden+, 2009)J/A+A/512/A41 : Abundances of microlensed stars in the Bulge (Bensby+, 2010)J/A+A/523/A17 : Individual stars in Fornax dSph center (Letarte+, 2010)J/A+A/511/L10 : Abundances and space velocities of 94 stars (Nissen+, 2010)J/ApJ/743/156 : NEOWISE obs. of NEOs; preliminary results (Mainzer+, 2011)J/A+A/564/A125 : AGN Torus model comparison of AGN in the CDFS (Buchner+, 2014)J/ApJ/807/171 : SkyMapper Survey metalpoor star spectroscopy (Jacobson+, 2015)J/ApJ/808/16 : The Cannon; new approach to determine abundances (Ness+, 2015)J/ApJ/823/114 : The Cannon; a new approach to determine masses (Ness+, 2016)J/ApJ/833/225 : -2.6<=[Fe/H]<=0.2 F and G dwarfs. II. Abundances (Zhao+, 2016)J/A+A/608/A46 : Constraining cosmic scatter (Reggiani+, 2017)J/ApJ/852/49 : Properties of metal-poor stars in APOGEE DR13 (Hayes+, 2018)J/ApJ/868/110 : R-Process Alliance; 1st release Galactic halo (Sakari+, 2018)J/A+A/627/A177 : Non-LTE analysis of K I in late-type stars (Reggiani+, 2019)J/ApJ/891/85 : Manganese abundances GC & dSph galaxies (de los Reyes+, 2020)J/AJ/160/181 : Chemical abundances in red giants with Magellan (Ji+, 2020)J/AJ/160/173 : Abundances metal-poor stars in Inner Bulge (Reggiani+, 2020)J/AJ/162/229 : 13 Magellanic Clouds metal-poor stars (Reggiani+, 2021)J/AJ/163/159 : Species abundances in WASP-77A (Reggiani+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/163/252https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/163/252http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/163/252https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/163/252https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/163/252http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/163/252GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/163/252/table1 (Log of observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/163/252/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/163/252/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/163/252/table1?GETtext/xml+votable180.050000true0.091166725.3227250.0055555555555555566/2347 12545 15872 16059 18682 20272 23110 25579 37034 37039 44890 46040 46227 46584 46604https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/163/252?format=asciiOpticaldefaultJ/AJ/163/252/table1Log of observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia EDR3 designationmeta.id;meta.maincharprimaryRAJ2000[0/23] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[02/78] Degree of declination (J2000)pos.eq.dec;meta.mainObs[2017/2018] UT year of observationstime.epochSlit[0.35/1.6] Slit widthspect.line.widthfloatTexp[300/4110] Exposure timestime.duration;obs.exposureintS/N4500[35/296] Signal-to-Noise ratio at 4500{AA}stat.snrintS/N6500[55/342] Signal-to-Noise ratio at 6500{AA}stat.snrintInstInstrument used; ARCES or MIKEinstr.setupcharNdataNumber of atomic data (table2)meta.numberintnullableNabundNumber of abundances (table4)meta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharJ/AJ/163/252/table2Atomic data, equivalent widths and line abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia EDR3 Designationmeta.id;meta.maincharWave[3729/7789] Wavelength; Angstroms0.1nmem.wldoubleSpeciesSpecies identifiermeta.idcharExPot[0/5.09] Excitation potentialeVphys.atmol.excitationfloatlogg[-5.97/0.54] log oscillator strengthphys.atmol.oscStrength;spect.line.strengthfloatEW[1.5/379]? Equivalent width; milli-Angstroms1e-13mspect.line.eqWidthfloatnullablelogx[-0.9/8.04] log number abundancemeta.numberfloatJ/AJ/163/252/table4Chemical abundancesGaiaGaia EDR3 Designationmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpecies identifiermeta.idcharN[1/76]? Number of lines usedmeta.numberintnullablelogx[-1.48/6.82]? log number abundancemeta.numberfloatnullable[X/Fe][-1.55/1.9]? log abundance relative to Fephys.abund;arith.zpfloatnullablee_[X/Fe][0.002/0.5]? Uncertainty in [X/Fe]stat.error;phys.abundfloatnullable