J/ApJ/860/125ivo://CDS.VizieR/J/ApJ/860/125doi:10.26093/cds/vizier.18600125CDSRoederer I.U.Sneden C.Lawler J.E.Sobeck J.S.Cowan J.J.,Boesgaard A.M.2019-11-04T14:46:04Z2019-07-31T14:03:22ZCDS support team

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

cds-question@unistra.frchemical-abundancesline-intensitieschemically-peculiar-starsspectroscopyultraviolet-astronomyvisible-astronomyNeutral Fe lines in metal-poor stars yield conflicting abundances depending on whether and how deviations from local thermodynamic equilibrium (LTE) are considered. We have collected new high-resolution and high signal-to-noise ultraviolet (UV) spectra of three warm dwarf stars with [Fe/H]~-2.9 with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. We locate archival UV spectra for three other warm dwarfs with [Fe/H]~-3.3, -2.2, and -1.6, supplemented with optical spectra for all six stars. We calculate stellar parameters using methods that are largely independent of the spectra, adopting broadband photometry, color-temperature relations, Gaia parallaxes, and assumed masses. We use the LTE line analysis code MOOG to derive Fe abundances from hundreds of FeI and FeII lines with wavelengths from 2290 to 6430{AA}. The [Fe/H] ratios derived separately from FeI and FeII lines agree in all six stars, with [FeII/H]-[FeI/H] ranging from +0.00+/-0.07 to -0.12+/-0.09dex, when strong lines and FeI lines with lower excitation potential <1.2eV are excluded. This constrains the extent of any deviations from LTE that may occur within this parameter range. While our result confirms non-LTE calculations for some warm, metal-poor dwarfs, it may not be generalizable to more metal-poor dwarfs, where deviations from LTE are predicted to be larger. We also investigate trends of systematically lower abundances derived from FeI lines in the Balmer continuum region (~3100-3700{AA}), and we conclude that no proposed explanation for this effect can fully account for the observations presently available.2018ApJ...860..125Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/860/125CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/eso : ESO Science Archive Catalog (ESO, 1991-2019)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)J/AJ/120/1841 : Abundances & Kinematics of Halo & Disk Stars (Fulbright 2000)J/A+A/377/361 : Fe II transition probabilities and loggf (Pickering+, 2001)J/AJ/124/1144 : Orbits of 171 single-lined spectrosc. binaries (Latham, 2002)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/A+A/435/373 : Broadening of Fe II lines by H collisions (Barklem+, 2005)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/A+A/493/601 : Lithium abundances of halo dwarfs (Hosford+, 2009)J/A+A/513/A35 : Abundances of Galactic red giants (Alves-Brito+, 2010)J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)J/ApJ/743/140 : Abundances (Be,{alpha}) in metal-poor stars (Boesgaard+, 2011)J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)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/773/33 : Chemical data of the metal-poor subgiant BD+44493 (Ito+, 2013)J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)J/ApJS/215/23 : FeI radiative lifetimes (Den Hartog+, 2014)J/A+A/564/A133 : Gaia FGK benchmark stars: metallicity (Jofre+, 2014)J/ApJS/215/20 : Vanadium log(gf) and transition probabilities (Lawler+, 2014)J/AJ/148/81 : APASS BVgri photometry of RAVE stars. I. Data (Munari+, 2014)J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)J/MNRAS/441/3127 : FeI oscillator strengths for Gaia-ESO (Ruffoni+, 2014)J/ApJS/214/18 : VII log(gf) values, and V abundance in HD 84937 (Wood+ 2014)J/ApJS/211/20 : NiI transition probability measurements (Wood+, 2014)J/ApJS/220/13 : Co I transition probabilities (Lawler+, 2015)J/A+A/580/A23 : Stroemgren-Crawford uvby{beta} photometry cat. (Paunzen, 2015)J/ApJS/216/1 : New FeI level energies from stellar spectra (Peterson+, 2015)J/A+A/582/A74 : WISE J072543.88-235119.7 line abundances (Spite+, 2015)J/ApJ/817/53 : Fe-group elemental abundances in HD84937 (Sneden+, 2016)J/ApJ/847/142 : Ultra-metal-poor stars LTE & NLTE abund. (Ezzeddine+, 2017)J/ApJS/229/23 : New FeI level energies. II. (Peterson+, 2017)J/A+A/608/A46 : Constraining cosmic scatter (Reggiani+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/860/125https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/860/125http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/860/125https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/860/125https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/860/125http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/860/125GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/860/125/table7 (Stellar parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/860/125/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/860/125/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/860/125/table7?GETtext/xml+votable180.050000true75.31926144.11028440.0055555555555555566/798 4376 23011 25385 26025 28336 35913https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/860/125?format=asciiUVOpticaldefaultJ/ApJ/860/125/table7Stellar parametersSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharprimaryf_Namea: Rederived; see Section 6.1meta.codecharTeff[6055/6625] Effective temperatureKphys.temperature.effectiveinte_Teff[73/137] log of surface gravityKstat.error;phys.temperature.effectiveintlogg[3.9/4.5] log of surface gravitylog(cm.s**-2)phys.gravityfloate_logg[0.1/0.3] logg uncertaintylog(cm.s**-2)stat.errorfloatVt[1.1/1.7] Microturbulent velocitykm/sphys.velocfloate_Vt[0.2] Vt uncertaintykm/sstat.errorfloat[M/H][-3.3/-1.6] Metallicityphys.abund.Zfloate_[M/H][0.1] [M/H] uncertaintystat.error;phys.abundfloatE230Display the Fe abundances from E230M and E230H spectra (link to Table 4)meta.ref.urlintnullableEWsDislay the equivalent widths for this star from Table 2meta.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/860/125/table2Fe line list, equivalent widths, and abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonSpecies (FeI or FeII)phys.atmol.ionStagecharlambda[2297.7/6430.9] Wavelength in Angstroms0.1nmem.wlfloatExPot[0/4.8] Excitation potential in eVeVphys.atmol.excitationfloatlog(gf)[-5/0.6] Log of degeneracy times oscillator strengthphys.atmol.oscStrengthfloatEW(BD+03_740)[1/105.4]? Equivalent with in milli Angstroms for BD+03 7400.1pmspect.line.eqWidthfloatnullableEW(BD-13_3442)[1.3/102.2]? Equivalent with in milli Angstroms for BD-13 34420.1pmspect.line.eqWidthfloatnullableEW(CD-33_1173)[1.3/99.3]? Equivalent with in milli Angstroms for CD-33 11730.1pmspect.line.eqWidthfloatnullableEW(G64-12)[1.8/99]? Equivalent with in milli Angstroms for G64-120.1pmspect.line.eqWidthfloatnullableEW(HD19445)[1/128.2]? Equivalent with in milli Angstroms for HD194450.1pmspect.line.eqWidthfloatnullableEW(HD84937)[1/132.3]? Equivalent with in milli Angstroms for HD849370.1pmspect.line.eqWidthfloatnullableEW(HD94028)[2.7/139.1]? Equivalent with in milli Angstroms for HD940280.1pmspect.line.eqWidthfloatnullableloge(BD+03_740)[4/5]? Log epsilon abundance for BD+03 740phys.abundfloatnullableloge(BD-13_3442)[4/5.1]? Log epsilon abundance for BD-133442phys.abundfloatnullableloge(CD-33_1173)[4/5]? Log epsilon abundance for CD-331173phys.abundfloatnullableloge(G64-12)[3.7/4.7]? Log epsilon abundance for G64-12phys.abundfloatnullableloge(HD19445)[5/5.8]? Log epsilon abundance for HD19445phys.abundfloatnullableloge(HD84937)[4.9/5.6]? Log epsilon abundance for HD84937phys.abundfloatnullableloge(HD94028)[5.5/6.3]? Log epsilon abundance for HD94028phys.abundfloatnullableJ/ApJ/860/125/table4Comparison of Fe equivalent widths and abundances from STIS -E230M (R~30000) and -E230H (R~114000) spectraNameStar (HD84937 or HD94028)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonSpecies (FeI or FeII)phys.atmol.ionStagecharlambda[2297.7/3100.7] Wavelength in Angstroms0.1nmem.wlfloatExPot[0/4] Excitation potential in eVeVphys.atmol.excitationfloatlog(gf)[-3.1/0.5] Log of degeneracy times oscillator strengthphys.atmol.oscStrengthfloatEW(E230M)[12.6/143] Equivalent width in milli Angstroms measured from E230M spectrum0.1pmspect.line.eqWidthfloatEW(E230H)[10.8/143.3] Equivalent width in milli Angstroms measured from E230H spectrum0.1pmspect.line.eqWidthfloatloge(E230M_EW)[4.5/6.3] Log epsilon abundance derived from EW measured from E230M spectrumphys.abundfloatloge(E230H_EW)[4.3/6.3] Log epsilon abundance derived from EW measured from E230H spectrumphys.abundfloatloge(E230M_s)[5/6.2] Log epsilon abundance derived from synthesis of E230M spectrumphys.abundfloatloge(E230H_s)[4.9/6.3] Log epsilon abundance derived from synthesis of E230H spectrumphys.abundfloat