J/A+A/330/505ivo://CDS.VizieR/J/A+A/330/505doi:10.26093/cds/vizier.33300505CDSBlanco A.Borghesi A.Fonti S.Orofino V.1998-04-01T13:46:21Z1998-04-01T12:43:32ZCDS support team

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

cds-question@unistra.frcarbon-starsinfrared-sourcesSpectroscopic and photometric data relative to a sample of 55 carbon stars showing the 11.3{mu}m feature have been fitted in the wavelength range between 0.4 and 100{mu}m by means of a radiative transfer model using the laboratory extinction spectra of amorphous carbon and silicon carbide (SiC) grains. The transfer code allows to determine in a self-consistent way the grain equilibrium temperature of the various species at different distances from the central star and gives all the relevant circumstellar parameters which can be very important for the evolutionary study of carbon stars. In order to get meaningful information on the nature and physical properties of the dust grains responsible for the 11.3{mu}m feature and the underlying continuum, the fitting procedure of the spectr a has been applied individually to every single source. For this reason it has been possible to take into account any variation in position and shape of the band from source to source. Our analysis show that all the sources, in addition to the amorphous carbon grains accounting for the continuum emission, need always the presence of {alpha}-SiC particles while some of them require also {beta}-SiC. Moreover, the presence of one or both types of SiC particles seems not correlated neither with the total optical thickness nor with any other physical and geometrical parameters of the circumstellar envelope. The best-fit parameters found in this work have been used to calculate the mass-loss rate from the central stars. The clear correlation, that we find between the strength of the SiC feature and the total mass loss-rate, confirms the results already found by other authors for the same kind of sources and derived from the observed CO emission lines.1998A&A...330..505Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/330/505CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/198 : Vilnius photometry of carbon stars (Paupers+, 1993)III/156 : Cool Galactic Carbon Stars, 2nd Edition (Stephenson 1989)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/330/505https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/330/505http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/330/505https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/330/505https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/330/505http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/330/505GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/A+A/330/505/table1The carbon star samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIRASIRAS namemeta.id;meta.maincharprimaryNameName from Yamashita (1972AnTok..13..169Y, 1975AnTok..15...47Y)meta.idcharSpTypeSpectral type from Yamashita (1972AnTok..13..169Y, 1975AnTok..15...47Y)src.spTypecharIRCIRC identification (Neugebauer & Leighton 1969IRC...C......0N)meta.idcharRAFGLRAFGL identification (Price & Murdock 1983AFGL..161.....P)meta.idcharCSNumber in the General Catalogue of Cool Carbon Stars (Stephenson 1989, Cat. <III/156>)meta.idint3umPresence and intensity of the band at 3{mu}m (1)meta.notechar8.6umPresence and intensity of the band at 8.6{mu}m (1)meta.notechar14umPresence and intensity of the band at 14{mu}m (1)meta.notecharJ/A+A/330/505/table2Best-fit model parameters of our IRAS source sample and computed mass-loss ratesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIRASIRAS namemeta.id;meta.maincharprimarytauOptical thicknessphys.absorption.opticalDepthfloatT*Stellar temperatureKphys.temperatureintRI/R*Enveloppe inner radius versus stellar radiuspos.distancefloatRE/RIEnveloppe outer radius versus stellar radiuspos.distancefloatACAC submicronic grains percentage%stat.paramintalpha{alpha}-SiC submicronic grains percentage%stat.paramintbeta? {beta}-SiC submicronic grains percentage%stat.paramintnullabledM/dtComputed mass-loss ratesolMass/yrphys.mass.lossfloat