J/ApJ/866/L1ivo://CDS.VizieR/J/ApJ/866/L1doi:10.26093/cds/vizier.18669001CDSSargent B.A.2019-10-31T08:32:01Z2019-10-31T09:28:46ZCDS support team

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

cds-question@unistra.frinfrared-astronomyspectroscopygiant-starsastronomical-modelsinterstellar-mediumMany emission features remain unidentified in the infrared spectra of asymptotic giant branch (AGB) stars. In particular, features at ~11, 20, 28, and 32{mu}m have been noted in mid-infrared spectra of oxygen-rich AGB stars. Here, I present models of dust excess emission in 36 spectra of 24 AGB stars from the Short Wavelength Spectrometer on board the Infrared Space Observatory and the Infrared Spectrograph on the Spitzer Space Telescope. The models include opacities of grains composed of mixtures of various polymorphs of alumina obtained by preparing bayerite and boehmite at high temperatures, and these dust components provide satisfactory fits to the 11, 20, 28, and 32{mu}m features. Though not a direct conclusion from this study, the presence of grains of the various polymorphs of aluminas in circumstellar dust shells around AGB stars suggests that corundum may have a role in giving rise to the 13{mu}m feature.2018ApJ...866L...1Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/866/L1CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)J/A+AS/146/437 : IR spectra of oxygen-rich evolved stars (Speck+, 2000)J/A+A/442/281 : Late-type giants BVRIJHKL & Teff calib. (Kucinskas+, 2005)J/A+A/483/661 : Refractive index for silicon carbide (SiC) (Pitman+, 2008)J/ApJ/693/L81 : Extinction in star-forming regions (McClure, 2009)J/ApJS/193/23 : Fundamental stellar parameters in 47 Tucanae (McDonald+, 2011)J/A+A/553/A81 : Refraction of corundum, spinel, {alpha}-quartz (Zeidler+, 2013)J/ApJ/811/45 : Infrared spectral properties of M giants (Sloan+, 2015)J/A+A/592/A42 : A study of dust nucleation in Mira. Part I. (Kaminski+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/866/L1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/866/L1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/866/L1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/866/L1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/866/L1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/866/L1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/866/L1/sample (List of the stars; table added by CDS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/866/L1/sample?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/866/L1/sample?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/866/L1/sample?GETtext/xml+votable180.050000true340.936993343.43341670.0055555555555555566/9813 9968 11165 13742 14170 16132 16783 18998 24418 30361 32254 33321 39230 40162 40448 41133 41852 42278 43227 45809 48301https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/866/L1?format=asciiInfrareddefaultJ/ApJ/866/L1/sampleList of the stars; table added by CDSSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTarget identifiermeta.id;meta.maincharprimaryGaiaDisplay the Gaia DR2 (I/345) within 2"meta.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/866/L1/table1information and dust model parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTarget identifiermeta.id;meta.maincharprimaryr_ID[abcdef] Flag on ID (1)meta.ref;pos.framecharDist[0.1/7.8]? Distance (2)kpcpos.distance;pos.heliocentricfloatnullablef_Dist[ghij] Flag on Dist (3)meta.codecharAv[0.01/1.6]? V band extinction (4)magphys.absorption;em.opt.Vfloatnullablef_Av[ghij] Flag on Av (3)meta.codecharInstSpitzer/IRS or ISO/SWS instrumentmeta.notecharAORSpitzer AOR or ISO AOT data identifiermeta.id;obsintModSclModule scalars (5)instr.setupcharTemp[56/1400] Model dust temperatureKphys.temperature;meta.modelledintAmEn[0/3.5e-14] Amorphous Enstatite mass weight (6)g.cm**-2phys.densitydoublee_AmEn[1.5e-22/1.4e-14] Uncertainty in AmEng.cm**-2stat.errordoubleCor[0/1.2e-13] Corundum mass weight (6)g.cm**-2phys.densitydoublee_Cor[3e-23/1.4e-13] Uncertainty in Corg.cm**-2stat.errordoubleBayer[0/1.2e-14] "Bayerite 1273K" mass weight (6)(7)g.cm**-2phys.densitydoublee_Bayer[5.8e-23/8.5e-16] Uncertainty in Bayerg.cm**-2stat.errordoubleAmAl[0/2.4e-14] Amorphous Alumina mass weight (6)g.cm**-2phys.densitydoublee_AmAl[9.5e-23/5.5e-15] Uncertainty in AmAlg.cm**-2stat.errordoubleBoe[0/3.8e-14] "Boehmite 1173K" mass weight (6)(7)g.cm**-2phys.densitydoublee_Boe[7.3e-23/2.2e-15] Uncertainty in Boeg.cm**-2stat.errordoubleChi2[0.8/1704]? Model {Chi}^2^/degrees of freedom value determined over 8.0<{lambda}<37umstat.fit.chi2doublenullable