J/AJ/149/11ivo://CDS.VizieR/J/AJ/149/11doi:10.26093/cds/vizier.51490011CDSSloan G.C.Herter T.L.Charmandaris V.Sheth K.Burgdorf M.Houck J.R.2018-05-30T10:52:15Z2015-06-02T15:10:51ZCDS support team

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

cds-question@unistra.frWe present spectra obtained with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope of 33 K giants and 20 A dwarfs to assess their suitability as spectrophotometric standard stars. The K giants confirm previous findings that the strength of the SiO absorption band at 8{mu}m increases for both later optical spectral classes and redder (B-V)_0_ colors, but with considerable scatter. For K giants, the synthetic spectra underpredict the strengths of the molecular bands from SiO and OH. For these reasons, the assumed true spectra for K giants should be based on neither the assumption that molecular band strengths in the infrared can be predicted accurately from optical spectral class or color nor synthetric spectra. The OH bands in K giants grow stronger with cooler stellar temperatures, and they are stronger than predicted by synthetic spectra. As a group, A dwarfs are better behaved and more predictable than the K giants, but they are more likely to show red excesses from debris disks. No suitable A dwarfs were located in parts of the sky continuously observable from Spitzer, and with previous means of estimating the true spectra of K giants ruled out, it was necessary to use models of A dwarfs to calibrate spectra of K giants from observed spectral ratios of the two groups and then use the calibrated K giants as standards for the full database of infrared spectra from Spitzer. We also describe a lingering artifact that affects the spectra of faint blue sources at 24{mu}m.2015AJ....149...11Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/149/11CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/149/11https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/149/11http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/149/11https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/149/11https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/149/11http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/149/11GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/149/11/spectra (The 33 K giants (table2) and 20 A darfs (table3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/149/11/spectra?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/149/11/spectra?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/149/11/spectra?GETtext/xml+votable180.050000true90.032125-64.310.0055555555555555566/6940 7239 10197 10217 11416 11423 11553 11734 11927 12255 12915 14126 15096 15153 15289 15291 15323 15327 15348 18463 22463 23426 25116 29199 32838 33193 33203 33351 33562 33794 33814 33875 33880 34240 37039 37164 37423 37428 37435 37520 37544 37546 38920 38924 39078 43233 43539 46982 47095 47298 490491.2932132981302573e-20 2.1346512726771855e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/149/11?format=asciiInfrareddefaultJ/AJ/149/11/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibCodemeta.bib.bibcodecharAutAuhtor's naemmeta.notecharRemRemarksmeta.notecharJ/AJ/149/11/spectraThe 33 K giants (table2) and 20 A darfs (table3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_Name[T] "T" Indicates that the spectrum is a template and not an IRS spectrummeta.codecharNameName of target used in filenames, in subdirectory spmeta.id;instr.setupcharHR[1014/8585]? Harvard Revised (V/50) numbermeta.idintnullableHD[15508/214873]? Henry Draper (III/135) numbermeta.idintnullableHIP[11364/175510] Hipparcos catalog (I/239) numbermeta.idintRAJ2000Hour of Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainSpT1Spectral type from the literaturesrc.spTypecharr_SpT1References for spectral type (the listed references are not meant to be complete); in refs.dat filemeta.ref;pos.framecharf_SpT2[b] Indicates that the SpT2 differs from the spectral class in the SpT1 columnmeta.codecharSpT2Modified spectral class (only in Table 2) (1)src.spTypecharf_S12[c] 12{mu}m flux from IRAS PSC (2)meta.codecharS12IRAS flux density S_{nu}_ at 12{mu}m (3)Jyphot.flux.density;em.IR.8-15umfloatNo[1/132] Number of Infrared Spectrograph (IRS) observations obtainedmeta.numberintNu[1/84] Number of IRS observations usedmeta.numberintspShow the spectrummeta.ref.urlchardataDisplay the spectral datameta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar