J/A+AS/129/289ivo://CDS.VizieR/J/A+AS/129/289CDSMoujtahid A.Zorec J.1998-06-11T15:58:17Z1998-06-11T15:58:14ZCDS support team

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

cds-question@unistra.frbe-starsspectrophotometryThe long-term spectrophotometric variations of 49 Be stars are studied using the U and V magnitudes of the UBV system, the total Balmer discontinuity D and the visible gradient {Phi}_rb_. BCD (Barbier-Chalonge-Divan, see Chalonge & Divan, 1952AnAp...15..201C) spectrophotometric and photometric data in five different photometric systems, obtained in most cases since 1950 and reduced to the BCD system, were used. The (U,D), (V,D), ({Phi}_rb_,D) and ({Phi}_rb_,V) correlations obtained differ from star to star and they can be single or double-valued. They differ clearly for Be phases or Be-shell phases. Be stars with small V.sin(i) showing the "spectrophotometric shell behaviour": D>D*, were found. This finding implies either that strongly flattened models of circumstellar envelopes are in doubt for these stars, or that not all Be stars are rapid rotators. Comparison of observed variations with those predicted for model Be stars with spherical circumstellar envelopes of variable densities and dimensions implies that spectrophotometric patterns of Be phases are due to circumstellar envelopes in low opacity regimes, while those of spectrophotometric shell phases are due to circumstellar envelopes in high opacity regimes. In a given star, the envelope regions responsible for the observed variations of D and {Phi}_rb_ in spectrophotometric shell phases seem to be smaller and denser than those producing the observed variations of these parameters in spectrophotometric Be phases. The high positive RV found in strong shell phases might favor the formation of compact circumstellar layers near the star.1998A&AS..129..289Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/129/289CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/187 : Classification of stars in BCD (Barbier/Chalonge/Divan)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/129/289https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/129/289http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/129/289https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/129/289https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/129/289http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/129/289GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+AS/129/289/stars (Star positions (from Simbad database))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+AS/129/289/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+AS/129/289/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+AS/129/289/stars?GETtext/xml+votable180.050000true11.18083348.2844440.005555555555555556https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+AS/129/289?format=asciiOpticaldefaultJ/A+AS/129/289/starsStar positions (from Simbad database)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDHD (Cat. <III/135>) numbermeta.id;meta.mainintprimaryRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination signpos.eq.dec;meta.mainJ/A+AS/129/289/table1The studied Be starsn_JDf[-] Dashmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDHD (Cat. <III/145>) numbermeta.id;meta.mainintprimaryHR? HR (Cat. <V/50>) numbermeta.idintnullableNameOther namemeta.idcharSpTypeSpectral typesrc.spTypecharn_SpType[a] Note on spectral type (1)meta.notecharFigFileFigure name in subdirectory figmeta.bib.figcharDstarStellar Balmer discontinuity magnitudemagphot.flux;arith.ratiofloatu_DstarUncertainty flag on Dstarmeta.code.errorcharn_Dstar[a] Note on Dstar (2)meta.notechar<Vmag>Average V magnitudemagphot.mag;em.opt.Vfloate_<Vmag>rms uncertainty on <Vmag>magstat.errorfloat<Dmag>Average total Balmer discontinuity magnitudemagphot.flux;arith.ratiofloate_<Dmag>rms uncertainty on <Dmag>magstat.errorfloat<Phirb>Average visible gradientmagarith.grad;phot.mag;em.optfloate_<Phirb>rms uncertainty on <Phirb>magstat.errorfloatJDfFirst observation date (-2400000)time.epochintJDlLast observation date (-2400000)time.epochintNNumber of individual triads (Vmag, Dmag, Phirb)meta.numberintRefReferences detailed in file refs.datmeta.refcharJ/A+AS/129/289/refsReferences of table1.datrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.refintprimaryBibCodeSimbad bibcodemeta.bib.bibcodecharAutAuthor name, and commentsmeta.bib.authorchar