J/ApJ/700/1216ivo://CDS.VizieR/J/ApJ/700/1216doi:10.26093/cds/vizier.17001216CDSMcSwain M.V.Huang W.Gies D.R.2017-12-06T07:38:39Z2011-09-07T07:47:34ZCDS support team

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

cds-question@unistra.fropen-star-clustersbe-starsvisible-astronomyspectroscopyeffective-temperaturestellar-massesWe recently discovered a large number of highly active Be stars in the open cluster NGC 3766, making it an excellent location to study the formation mechanism of Be star disks. To explore whether similar disk appearances and/or disappearances are common among the Be stars in other open clusters, we present here multiple epochs of H{alpha} spectroscopy for 296 stars in eight open clusters. We identify 12 new transient Be stars and confirm 17 additional Be stars with relatively stable disks. By comparing the H{alpha} equivalent widths to the photometric y-H{alpha} colors, we present a method to estimate the strength of the H{alpha} emission when spectroscopy is not available. For a subset of 128 stars in four open clusters, we also use blue optical spectroscopy and available Stromgren photometry to measure their projected rotational velocities, effective temperatures, and polar surface gravities. We combine our Be star detections from these four clusters to investigate physical differences between the transient Be stars, stable Be stars, and normal B-type stars with no line emission. Both types of Be stars are faster rotating populations than normal B-type stars, and we find no significant physical differences between the transient and stable Be stars in our sample.2009ApJ...700.1216Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/700/1216CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/386/447 : RV catalogue of O-type stars in NGC 6231 (Sana+, 2008)J/A+A/457/265 : The VLT-FLAMES Survey of Massive Stars (Dufton+, 2006)J/ApJS/161/118 : byH{alpha} photometry in open clusters (McSwain+, 2005)J/ApJ/622/1052 : byH{alpha} photometry of NGC 3766 (McSwain+, 2005)J/A+A/402/549 : UBVRIHalpha photometry of NGC 3293 (Baume+, 2003)J/A+A/395/823 : CCD {Delta}a-photometry of 5 open clusters (Paunzen+, 2002)J/A+A/369/511 : Open star clusters. III. NGC 4103, 5281, 4755 (Sanner+, 2001)J/AJ/115/734 : NGC 6231 UBVRI and H{alpha} photometry (Sung+ 1998)J/A+A/315/384 : Binarity among B-stars in NGC 6231 (Raboud, 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/700/1216https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/700/1216http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/700/1216https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/700/1216https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/700/1216http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/700/1216GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/700/1216/table2 (H{alpha} equivalent widths)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/700/1216/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/700/1216/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/700/1216/table2?GETtext/xml+votable180.050000true202.4998333-61.10050.005555555555555556Cone search capability for table J/ApJ/700/1216/table5 (Physical parameters of cluster members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/700/1216/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/700/1216/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/700/1216/table5?GETtext/xml+votable180.050000true158.9788333-58.11361110.0055555555555555566/29533 37901 37912 38018 38019 38024 38025 38026 41697 41699 42394 43027 43030 43033 43036https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/700/1216?format=asciiOpticaldefaultJ/ApJ/700/1216/table2H{alpha} equivalent widthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClCluster identification (1)meta.id.parentcharMGStar identification in clustermeta.idintn_MGSimbad column added by the CDSmeta.notecharWHa05? H{alpha} equivalent width in 2005 Feb (2)0.1nmspect.line.eqWidth;em.line.HalphafloatnullableWHa06? H{alpha} equivalent width in 2006 May (2)0.1nmspect.line.eqWidth;em.line.HalphafloatnullableWHa07? H{alpha} equivalent width in 2007 May (2)0.1nmspect.line.eqWidth;em.line.HalphafloatnullableEm2Be stars and candidates found in our photometry (Paper II, Cat. J/ApJS/161/118)src.spTypecharEmBe star status based upon our red spectroscopic observations only; in this worksrc.spTypechar_RAPositions from Paper II (McSwain & Gies 2005, Cat. J/ApJS/161/118) (right ascension part)degpos.eq.ra;meta.main_DEPositions from Paper II (McSwain & Gies 2005, Cat. J/ApJS/161/118) (declination part)degpos.eq.dec;meta.mainJ/ApJ/700/1216/table5Physical parameters of cluster memberse_Teff? Teff uncertaintyKstat.error;phys.temperature.effectiveintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintsp[Be ] Spectral class: B or Be starsrc.spTypecharClCluster identification (<NGC NNNN> in Simbad)meta.id.parentcharMGStar identification in clustermeta.idintn_MGSimbad column added by the CDSmeta.notecharvsini? Rotational velocitykm/sphys.veloc.rotatintnullablee_vsini? vsini uncertaintykm/sstat.error;phys.veloc.rotatintnullableTeff? Effective temperatureKphys.temperature.effectiveintnullablelogg? Surface gravitylog(cm.s**-2)phys.gravityfloatnullablee_logg? logg uncertaintylog(cm.s**-2)stat.errorfloatnullableloggP? Polar surface gravitylog(cm.s**-2)phys.gravityfloatnullableMass? Mass (M_*_)solMassphys.massfloatnullablee_Mass? Mass uncertaintysolMassstat.error;phys.massfloatnullableRad? Radius (R_*_)solRadphys.size.radiusfloatnullablee_Rad? Rad uncertaintysolRadstat.errorfloatnullableVc? Critical velocity (1)km/sphys.veloc.escapeintnullableSB?Binarity commentmeta.code.multipcharAutAuthor's name for SB? remarkmeta.bib.authorcharBibCodeBibcode for SB? remarkmeta.bib.bibcodecharSimbadNameSimbad column added by the CDSmeta.idchar_RAPositions from Paper II (McSwain & Gies 2005, Cat. J/ApJS/161/118) (right ascension part)degpos.eq.ra;meta.main_DEPositions from Paper II (McSwain & Gies 2005, Cat. J/ApJS/161/118) (declination part)degpos.eq.dec;meta.main