J/MNRAS/493/4463ivo://CDS.VizieR/J/MNRAS/493/4463doi:10.26093/cds/vizier.74934463CDSDo-Duy T.Wright C.M.Fujiyoshi T.Glasse A.Siebenmorgen R.Smith R.,Stecklum B.Sterzik M.2024-08-20T20:16:42Z2023-07-24T08:26:08ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsinterstellar-mediumh-ii-regionsinfrared-astronomyspectroscopyUtilizing several instruments on 4-8m telescopes, we have observed a large sample of objects in the mid-infrared (8-13{mu}m). These comprise a few evolved stars, multiple envelopes of embedded young stellar objects (YSOs) or compact H-II regions, and several sightlines through the interstellar medium (ISM). The latter is where dust resides - and is potentially modified - between its formation in evolved stellar outflows and deposition in molecular clouds. In most objects, we detect not only the well-known 9.7{mu}m absorption feature of amorphous silicates but also a second absorption band around 11.1{mu}m whose carrier is attributed to crystalline forsterite. We propose that crystalline silicates are essentially ubiquitous in the ISM and earliest phases of star formation, and are evolutionary precursors to T-Tauri and Herbig stars where such silicates have been commonly found. Modelling shows that in most YSOs, H-II regions and ISM cases, the forsterite mass fraction is between 1 and 2 per cent, suggesting that the younger phases inherit their abundance from the ISM. However, several sources show much stronger features (abundances >=3 per cent). This suggests that significant processing, perhaps crystallization by thermal annealing, occurs early on in star formation. Most intriguing is the first detection of crystalline silicate in the diffuse ISM. We propose that our observed abundance is consistent with a mass fraction of crystalline silicates of 10-20 per cent injected into the ISM, along with commonly accepted lifetimes against their destruction, but only if cosmic ray-induced amorphization is insignificant over a few Giga years.2020MNRAS.493.4463Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/493/4463CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/493/4463https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/493/4463http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/493/4463https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/493/4463https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/493/4463http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/493/4463GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/493/4463/table1 (Observation log)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/493/4463/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/493/4463/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/493/4463/table1?GETtext/xml+votable180.050000true292.622813919.84473190.005555555555555556Cone search capability for table J/MNRAS/493/4463/table2 (Comparisons of optical depths at different wavelengths)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/493/4463/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/493/4463/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/493/4463/table2?GETtext/xml+votable180.050000true278.5871292-5.99506390.0055555555555555566/3198 3649 14063 14287 14317 14336 14624 14632 14689 15667 21430 21439 21458 21523 21643 22243 22855 22876 23549 23636-23637 23969 24325 28830 29095 29504 29529 30241 30315 37850 37923 41655 41676-41677 47828https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/493/4463?format=asciiInfrareddefaultJ/MNRAS/493/4463/table1Observation logSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMoreLink to Tables 2, 3, 5 and 8meta.ref.urlcharNameSource namemeta.id;meta.maincharprimaryn_Name[*+] Note on Name (1)meta.notecharf_Name[EYS] Flag on Name (G1)meta.codecharDateDate of observationtime.epochcharInstInstrument used for the observation (2)instr.setupcharPAslitSlit position angledegpos.posAngfloatChopChop throwarcsecinstr.setupfloatNodNod throwdeginstr.setupfloatStdStarStandard starmeta.idcharAirmassSrcAirmass of the sourceobs.airMassfloatAirmassStdAirmass of the standard starobs.airMassfloatISOIDISO identifiermeta.idcharTypeType of the object (3)src.classchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/MNRAS/493/4463/table2Comparisons of optical depths at different wavelengthse_tau3.0? Error on tau3.0stat.errorfloatnullabletau3.25? Optical depth at 3.25umphys.absorption.opticalDepthfloatnullableSimbadNameSimbad column added by the CDSmeta.idcharnullabletau6.2? Optical depth at 6.2umphys.absorption.opticalDepthfloatnullablee_tau6.2? Error on tau6.2stat.errorfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharf_Name[YI] Flag on Name (1)meta.codechartau11.1? Optical depth at 11.1umphys.absorption.opticalDepthfloatnullablee_tau11.1? Error on tau11.1stat.errorfloatnullabletau3.0? Optical depth at 3.0umphys.absorption.opticalDepthfloatnullablee_tau3.25? Error on tau3.25stat.errorfloatnullabletau3.4? Optical depth at 3.4umphys.absorption.opticalDepthfloatnullablee_tau3.4? Error on tau3.4stat.errorfloatnullabletau3.47? Optical depth at 3.47umphys.absorption.opticalDepthfloatnullablee_tau3.47? Error on tau3.47stat.errorfloatnullabletau4.27? Optical depth at 4.27umphys.absorption.opticalDepthfloatnullablee_tau4.27? Error on tau4.27stat.errorfloatnullabletau6.0? Optical depth at 6.0umphys.absorption.opticalDepthfloatnullablee_tau6.0? Error on tau6.0stat.errorfloatnullablel_tau6.2Limit flag on tau6.2meta.code.errorchartau6.85? Optical depth at 6.85umphys.absorption.opticalDepthfloatnullablee_tau6.85? Error on tau6.85stat.errorfloatnullableB_tau6.85? Upper bound on tau6.85meta.notefloatnullableRefReferencesmeta.refchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/MNRAS/493/4463/table3Asymmetric Gaussian fit parameters for the 11.1um feature and independent estimates of {tau}_9.7_recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharInstIntrument used (G2)instr.setupcharf_Name[EYS] Flag on Name (G1)meta.codechartau11.1? Optical depth at 11.1umphys.absorption.opticalDepthfloatnullablef_tau11.1[e] Flag on tau11.1 (1)meta.codechare_tau11.1? Error on tau11.1stat.errorfloatnullablelambdac? Central wavelength of the 11.1um featureumem.wl.centralfloatnullablee_lambdac? Error on lambdacumstat.errorfloatnullableFWHM? FWHM of the 11.1um featureumspect.line.widthfloatnullablee_FWHM? Error on FWHMumstat.error;phys.angSizefloatnullabletau9.7ap? Optical depth at 9.7um evaluated by eyeball estimationphys.absorption.opticalDepthfloatnullablee_tau9.7ap? Error on tau9.7apstat.errorfloatnullabletau9.7bf? Optical depth at 9.7um evaluated by the best fit with optically thick modelphys.absorption.opticalDepth;meta.modelledfloatnullablee_tau9.7bf? Error on tau9.7bfstat.errorfloatnullabletau9.7ot? Optical depth at 9.7um evaluated by the best fit with optically thin modelphys.absorption.opticalDepth;meta.modelledfloatnullablee_tau9.7ot? Error on tau9.7otstat.errorfloatnullableJ/MNRAS/493/4463/table5Mass fraction (per cent) of each component over the total mass of the silicate dust in the spectral fitsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource Namemeta.id;meta.maincharInstIntrument used (G2)instr.setupcharf_Name[EYS] Flag on Name (G1)meta.codecharOlisg? Mass fraction of small grain Olivine (0.1um)%phys.mass;arith.ratiofloatnullablee_Olisg? Error on Olisg%stat.errorfloatnullableOlilg? Mass fraction of large grain Olivine (2um)%phys.mass;arith.ratiofloatnullablee_Olilg? Error on Olilg%stat.errorfloatnullablePyrsg? Mass fraction of small grain Pyroxene (0.1um)%phys.mass;arith.ratiofloatnullablee_Pyrsg? Error on Pyrsg%stat.errorfloatnullablePyrlg? Mass fraction of large grain Pyroxene (2um)%phys.mass;arith.ratiofloatnullablee_Pyrlg? Error on Pyrlg%stat.errorfloatnullableForsMass fraction of 0.1um-grain Forsterite%phys.mass;arith.ratiofloate_ForsError on Fors%stat.errorfloatEnst? Mass fraction of 0.1um-grain Enstatite%phys.mass;arith.ratiofloatnullablee_Enst? Error on Enst%stat.errorfloatnullablechi2Reduced chi-squared of the spectral fit%stat.fit.chi2floatJ/MNRAS/493/4463/table8Optically thin model - mass fraction (per cent) and {chi}^2^ for each spectral fitInstIntrument used (G2)instr.setupcharf_Name[EYO] Flag on Name (1)meta.codecharOlisgMass fraction of small grain Olivine (0.1um)%phys.mass;arith.ratiofloate_OlisgError on Olisg%stat.errorfloatOlilg? Mass fraction of large grain Olivine (2um)%phys.mass;arith.ratiofloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.mainchare_Olilg? Error on Olilg%stat.errorfloatnullablePyrsgMass fraction of small grain Pyroxene (0.1um)%phys.mass;arith.ratiofloate_PyrsgError on Pyrsg%stat.errorfloatPyrlg? Mass fraction of large grain Pyroxene (2um)%phys.mass;arith.ratiofloatnullablee_Pyrlg? Error on Pyrlg%stat.errorfloatnullableForsMass fraction of 0.1um-grain Forsterite%phys.mass;arith.ratiofloate_ForsError on Fors%stat.errorfloatEnst? Mass fraction of 0.1um-grain Enstatite%phys.mass;arith.ratiofloatnullablee_Enst? Error on Enst%stat.errorfloatnullablechi2thinReduced chi-squared of the optically thin model spectral fit%stat.fit.chi2floatchi2thick? Reduced chi-squared of the optically thick model spectral fit (same as Table 5)%stat.fit.chi2floatnullableJ/MNRAS/493/4463/refsReferences for Table 2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRef[1/34] Reference numbermeta.id;meta.mainintBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar