J/AJ/165/55ivo://CDS.VizieR/J/AJ/165/55doi:10.26093/cds/vizier.51650055CDSChiti A.Frebel A.Ji A.P.Mardini M.K.Ou X.Simon J.D.Jerjen H.,Kim D.Norris J.E.2024-11-12T20:09:17Z2023-06-13T06:58:59ZCDS support team

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

cds-question@unistra.frdwarf-galaxiespopulation-ii-starsvisible-astronomyspectroscopychemical-abundancesradial-velocityeffective-temperatureWe present chemical abundances and velocities of five stars between 0.3 and 1.1kpc from the center of the TucanaII ultrafaint dwarf galaxy (UFD) from high-resolution Magellan/MIKE spectroscopy. We find that every star is deficient in metals (-3.6<[Fe/H]<-1.9) and in neutron-capture elements as is characteristic of UFD stars, unambiguously confirming their association with TucanaII. Other chemical abundances (e.g., C, iron peak) largely follow UFD trends and suggest that faint core-collapse supernovae (SNe) dominated the early evolution of TucanaII. We see a downturn in [{alpha}/Fe] at [Fe/H]~-2.8, indicating the onset of Type Ia SN enrichment and somewhat extended chemical evolution. The most metal-rich star has strikingly low [Sc/Fe]=-1.29{+/-}0.48 and [Mn/Fe]=-1.33{+/-}0.33, implying significant enrichment by a sub-Chandrasekhar mass Type Ia SN. We do not detect a radial velocity gradient in TucanaII (dv_helio_/d{theta}_1_=-2.6_-2.9_^+3.0^km/s/kpc), reflecting a lack of evidence for tidal disruption, and derive a dynamical mass of M_1/2_(r_h_)=1.6_-0.7_^+1.1^x10^6^M{sun}. We revisit formation scenarios of the extended component of TucanaII in light of its stellar chemical abundances. We find no evidence that TucanaII had abnormally energetic SNe, suggesting that if SNe drove in situ stellar halo formation, then other UFDs should show similar such features. Although not a unique explanation, the decline in [{alpha}/Fe] is consistent with an early galactic merger triggering later star formation. Future observations may disentangle such formation channels of UFD outskirts.2023AJ....165...55Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/165/55CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/ApJ/612/447 : Draco 119 and HD 88609 equivalent widths (Fulbright+, 2004)J/ApJ/645/613 : Abundances of HD 221170 (Ivans+, 2006)J/ApJS/162/227 : Transition probabilities for SmII (Lawler+, 2006)J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)J/ApJS/182/51 : Transition probabilities rare earth elements (Lawler+, 2009)J/ApJS/182/80 : Rare earth abundances (Sneden+, 2009)J/ApJ/708/560 : Spectroscopy of UMa II and Coma Ber (Frebel+, 2010)J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)J/ApJ/723/1632 : Abundance spreads in Bootes I and Segue 1 (Norris+, 2010)J/ApJ/711/350 : Metal-poor giant Boo-1137 abundances (Norris+, 2010)J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)J/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/763/61 : Abundances of 7 red giant members of BootesI (Gilmore+, 2013)J/ApJ/778/149 : Abundances for 3 stars in Sgr dSph (McWilliam+, 2013)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/571/A47 : Extensive linelist CH in stellar atmospheres (Masseron+, 2014)J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)J/MNRAS/440/2665 : SDSS J021933.13+200830.2 spectroscopy (Roederer+, 2014)J/AJ/147/136 : Stars of low metal abundance. VI. Abundances (Roederer+, 2014)J/ApJ/801/125 : Carbon in red giants in GCs and dSph galaxies (Kirby+, 2015)J/ApJ/802/93 : Chemical abundance analysis 5 stars in Sculptor (Simon+, 2015)J/A+A/574/A129 : The First CEMP star in the Sculptor dSph (Skuladottir+, 2015)J/ApJ/808/108 : M2FS stellar spectroscopy of Reticulum 2 (Walker+, 2015)J/ApJ/826/110 : Boo-127 and Boo-980 high-resolution spectra (Frebel+, 2016)J/ApJ/830/93 : Abundances of Ret II brightest red giant members (Ji+, 2016)J/A+A/586/A120 : Grid of 1D models for Mg line formation (Osorio+, 2016)J/AJ/151/82 : 4 brightest red giants in UFD galaxy Ret 2 (Roederer+, 2016)J/ApJ/819/53 : Magellan/M2FS spectroscopy of Tucana2 & Grus1 (Walker+, 2016)J/ApJ/838/44 : Abundances of the brightest member of Tuc III (Hansen+, 2017)J/ApJ/838/83 : RVel, abundances & membership in TriII (Kirby+, 2017)J/A+A/606/A112 : Abundance analysis of ALW Carina 8 (Susmitha+, 2017)J/ApJ/857/74 : Abundances of 7 new member stars in Tucana II (Chiti+, 2018)J/ApJ/856/142 : Abundances of metal-poor stars in Sculptor (Chiti+, 2018)J/ApJ/855/83 : Abundances of metal-poor stars in Sagittarius (Hansen+, 2018)J/ApJ/866/22 : Spectroscopic analysis of Tuc III stream (Li+, 2018)J/ApJ/852/99 : Abundances 3 metal-poor starsHorologium I (Nagasawa+, 2018)J/ApJ/863/89 : Gaia DR2 PMs stars in ultra-faint MW satellites (Simon, 2018)J/A+A/631/A80 : Mn lines 3D NLTE formation late-type stars (Bergemann+, 2019)J/A+A/626/A15 : Sculptor Red Giant Branch stars abundances (Hill+, 2019)J/ApJ/870/83 : Abundances in ultra-faint dwarf gal. GruI & TriII (Ji+, 2019)J/ApJ/882/177 : Abundances of 4 member stars of Tucana III (Marshall+, 2019)J/ApJ/891/85 : Mn abundances in GC & dSph galaxies (de los Reyes+, 2020)J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)J/ApJ/897/183 : Chemical abundances 3 stars in Grus II galaxy (Hansen+, 2020)J/AJ/160/181 : Chemical abundances in red giants with Magellan (Ji+, 2020)J/ApJ/889/27 : Abundances of 11 stars in Carina II and III (Ji+, 2020)J/ApJ/909/192 : HST/ACS photometry of Eridanus II (Gallart+, 2021)J/ApJ/908/18 : HST stellar photometry of Eridanus II (Simon+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/165/55https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/165/55http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/165/55https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/165/55https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/165/55http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/165/55GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/165/55/stars (Parameters for observed stars (paste table1 and table2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/165/55/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/165/55/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/165/55/stars?GETtext/xml+votable180.050000true342.68790417-58.939023060.005555555555555556Cone search capability for table J/AJ/165/55/table6 (*Velocity measurements)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/165/55/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/165/55/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/165/55/table6?GETtext/xml+votable180.050000true342.92942-58.542690.0055555555555555566/46126 46138 46209 46212-46213https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/165/55?format=asciiOpticaldefaultJ/AJ/165/55/starsParameters for observed stars (paste table1 and table2)SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[22] Hour of right ascension (J2000)pos.eq.ra;meta.mainNameName from Chiti+, 2021NatAs...5..392Cmeta.id;meta.maincharprimaryObsUT date(s) of observationtime.epoch;obscharSlit[1] Slit sizesinstr.setupfloatgmag[18.3/18.9] g-band magnitudemagphot.mag;em.opt.VfloatTexp[150/365] Exposure timemintime.duration;obs.exposureinte_Teff[160/241] Error on TeffKstat.error;phys.temperature.effectiveintDEJ2000[57/58] Degree of declination (J2000)pos.eq.dec;meta.mainS/N4500[12/19] Signal-to-noise ratio at 4500{AA}stat.snrintS/N6500[22/40] Signal-to-noise ratio at 6500{AA}stat.snrintRVel[-129/-119] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVel[0.9] Error on RVelkm/sstat.error;spect.dopplerVelocfloatTeff[4810/5071] Effective temperatureKphys.temperature.effectiveintlogg[1.55/1.75] log surface gravityphys.gravityfloate_logg[0.3/0.9] Error on loggstat.errorfloatnu[1.73/2.3] microturbulence velocitykm/sphys.veloc.microTurbfloate_nu[0.2/0.3] Error on nukm/sstat.errorfloat[Fe/H][-3.59/-1.93] log metallicityphys.abund.Fefloate_[Fe/H][0.1/0.3] Error on [Fe/H]stat.error;phys.abund.FefloatJ/AJ/165/55/table3Chemical abundancesNameStar identifiermeta.id;meta.maincharsigma[0.17/0.65]? Random uncertainty in abundances (3)stat.error;phys.abundfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpecies identifiermeta.idcharf_Species[b] Flag on Species (1)meta.codecharN[1/126] Number of lines usedmeta.numberintlogeX[0.52/8.43] log solar number abundancephys.abundfloatl_[X/H]Limit flag on [X/H]meta.code.error;phys.abundchar[X/H][-4.99/-1.29] log abundance relative to Hydrogenphys.abund;arith.ratiofloatu_[X/H][:] Uncertainty flag on [X/H] (9 occurrences) (2)meta.code.error;phys.abundcharl_[X/Fe]Limit flag on [X/Fe]meta.code.error;phys.abundchar[X/Fe][-2.09/1.45] log abundance relative to Ironphys.abundfloatu_[X/Fe][:] Uncertainty in [X/Fe] (9 occurrences) (2)meta.code.error;phys.abundcharJ/AJ/165/55/table4UncertaintiesNameStar identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpecies identifiermeta.idcharN[1/126] Number of lines usedmeta.numberintsigma[0.17/0.65]? Random uncertaintystat.error;phys.abundfloatnullable[X/H]sys[0.09/0.79]? log systematic abundance uncertainty relative to Hydrogenstat.error;phys.abundfloatnullable[X/H]tot[0.25/0.82]? log total abundance uncertainty relative to Hydrogenstat.error;phys.abundfloatnullable[X/Fe]sys[0.01/0.65]? log systematic abundance uncertainty relative to Ironstat.error;phys.abundfloatnullable[X/Fe]tot[0.17/0.71]? log total abundance uncertainty relative to Ironstat.error;phys.abundfloatnullableJ/AJ/165/55/table5Line measurementsNameStar identifiermeta.id;meta.maincharlogeX[-2.56/7.02] log number abundancephys.abundfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWave[3787/6979] Rest wavelength; Angstroms0.1nmem.wlfloatSpeciesSpecies identifiermeta.idcharExPot[0/4.45]? Excitation potential (1)eVphys.atmol.excitationfloatnullablel_logeXLimit flag on loge(X)meta.code.errorcharloggf[-5.69/0.65]? Oscillator strength (1)phys.atmol.oscStrengthfloatnullableEW[22.3/244]? Equivalent width; m{AA} (1)1e-13mspect.line.eqWidthfloatnullableJ/AJ/165/55/table6*Velocity measurementse_RVel[0.5/9] Error on RVelkm/sstat.error;spect.dopplerVelocfloatRef[1/5] Reference used (3)meta.refintInstInstrument used (1)meta.id;instrcharRVel[-136/-115] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifiermeta.id;meta.maincharRAJ2000[342/345] Degree of Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-59/-57] Degree of Declination (J2000)degpos.eq.dec;meta.mainMJD[57221/59494] Modified Julian Date at midpoint of the observation (JD-2400000.5)dtime.epochfloatf_RVel[b] Flag on RVel (2)meta.codechar