J/A+A/610/A30ivo://CDS.VizieR/J/A+A/610/A30doi:10.26093/cds/vizier.36100030CDSAidelman Y.Cidale L.S.Zorec J.Panei J.A.2019-04-04T13:26:42Z2018-02-21T16:11:15ZCDS support team

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

cds-question@unistra.frb-starsspectrophotometryobservational-astronomyStellar physical properties of star clusters are poorly known and the cluster parameters are often very uncertain. Our goals are to perform a spectrophotometric study of the B star population in open clusters to derive accurate stellar parameters, search for the presence of circumstellar envelopes, and discuss the characteristics of these stars. The BCD spectrophotometric system is a powerful method to obtain stellar fundamental parameters from direct measurements of the Balmer discontinuity. To this end, we wrote the interactive code MIDE3700. The BCD parameters can also be used to infer the main properties of open clusters: distance modulus, color excess, and age. Furthermore, we inspected the Balmer discontinuity to provide evidence for the presence of circumstellar disks and identify Be star candidates. We used an additional set of high-resolution spectra in the H{alpha} region to confirm the Be nature of these stars. We provide Teff, logg, Mv, Mbol, and spectral types for a sample of 68 stars in the field of the open clusters NGC6087, NGC6250, NGC6383, and NGC6530, as well as the cluster distances, ages, and reddening. Then, based on a sample of 230 B stars in the direction of the 11 open clusters studied along this series of three papers, we report 6 new Be stars, 4 blue straggler candidates, and 15 B-type stars (called Bdd) with a double Balmer discontinuity, which indicates the presence of circumstellar envelopes. We discuss the distribution of the fraction of B, Be, and Bdd star cluster members per spectral subtype. The majority of the Be stars are dwarfs and present a maximum at the spectral type B2-B4 in young and intermediate-age open clusters (<40Myr). Another maximum of Be stars is observed at the spectral type B6-B8 in open clusters older than 40Myr, where the population of Bdd stars also becomes relevant. The Bdd stars seem to be in a passive emission phase. Our results support previous statements that the Be phenomenon is present along the whole main sequence band and occurs in very different evolutionary states.We find clear evidence of an increase of stars with circumstellar envelopes with cluster age. The Be phenomenon reaches its maximum in clusters of intermediate age (10-40Myr) and the number of B stars with circumstellar envelopes (Be plus Bdd stars) is also high for the older clusters (40-100Myr).2018A&A...610A..30Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/610/A30CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/610/A30https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/610/A30http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/610/A30https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/610/A30https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/610/A30http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/610/A30GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/610/A30/table1 (Log of observations of low-resolution spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/610/A30/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/610/A30/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/610/A30/table1?GETtext/xml+votable180.050000true244.6566667-57.69612780.005555555555555556Cone search capability for table J/A+A/610/A30/table2 (Log of observations of high-resolution spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/610/A30/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/610/A30/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/610/A30/table2?GETtext/xml+votable180.050000true157.3904167-60.21039440.0055555555555555566/28809 28890-28891 28919 37334 37340 37349 37351 37901 37912 39233 41439 41445 41461 41699 42194 42370-42371 42376 42380 43033https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/610/A30?format=asciidefaultJ/A+A/610/A30/table1Log of observations of low-resolution spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay all data for this starmeta.ref.urlcharClOpen cluster namemeta.id.parentcharStar? Star number within the cluster (G1)meta.idintnullableONameOther designationmeta.id;meta.maincharRAJ2000Right ascension (Eq=J2000 (Ep=2000)pos.eq.ra;meta.mainDEJ2000Declination (Eq=J2000, Ep=2000)pos.eq.dec;meta.mainAM1Air mass of first observationobs.airMassfloatAM2? Air mass of second observationobs.airMassfloatnullableAM3? Air mass of third observationobs.airMassfloatnullableDate1Date of first observationtime.epochnullableDate2Date of second observationtime.epochnullableDate3Date of third observationtime.epochnullableNNumber of observationsmeta.numberintSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/610/A30/table2Log of observations of high-resolution spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClOpen cluster namemeta.id.parentcharStar? Star number within the cluster (G1)meta.idintnullableONameOther designationmeta.id;meta.maincharRAJ2000Right ascension (Eq=J2000 (Ep=2000)pos.eq.ra;meta.mainDEJ2000Declination (Eq=J2000, Ep=2000)pos.eq.dec;meta.mainAM1Air mass of first observationobs.airMassfloatAM2? Air mass of second observationobs.airMassfloatnullableAM3? Air mass of third observationobs.airMassfloatnullableDate1Date of first observationtime.epochnullableDate2Date of second observationtime.epochnullableDate3Date of third observationtime.epochnullableNNumber of observationsmeta.numberintJ/A+A/610/A30/stelparamStellar fundamental parameters for NGC 6087 (table 9), NGC 6250 (table 11), NGC 6383 (table13) and NGC 6530 (table 15)SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay all data for this starmeta.ref.urlcharClOpen cluster namemeta.id.parentcharStar? Star number within the cluster (G1)meta.idintnullableONameOther designationmeta.id;meta.maincharn_OName[dd ] Second Balmer Discontinuity (2)meta.notecharDPhotospheric component of the Balmer discontinuitypos.cartesianfloatlambda1? Mean spectral position of the Balmer discontinuity0.1nmem.wlintnullablePhibObserved color gradientumarith.grad;phot.colorfloatSpTypeSpectral typesrc.spTypecharn_SpTypeOther object types (3)meta.notecharTeffEffective TemperatureKphys.temperature.effectiveintn_Teff[man: ] Extrapolated values flag for Teff (4)meta.notechare_TeffError in Effective TemperatureKstat.error;phys.temperature.effectiveintloggStellar surface gravitylog(cm.s**-2)phys.gravityfloatn_logg[man: ] Extrapolated values flag for logg (4)meta.notechare_loggError in logglog(cm.s**-2)stat.errorfloatVMAGAbsolute Magnitude in V filtermagphys.magAbs;em.opt.Vfloatn_VMAG[man: ] Extrapolated values flag for VMAG (4)meta.notechare_VMAGError in Absolute Magnitudemagstat.errorfloatMbolBolometric Magnitudemagphys.magAbs.bolfloatn_Mbol[man: ] Extrapolated values flag for Mbol (4)meta.notechare_MbolError in Bolometric Magnitudemagstat.errorfloatPhi0Intrinsic color gradientumarith.grad;phot.colorfloatn_Phi0[man: ] Extrapolated values flag fro Phi0 (4)meta.notechare_Phi0Error in Intrinsic color gradientumstat.errorfloatJ/A+A/610/A30/physparamPhysical parameters and distances for NGC 6087 (table 10), NGC 6250 (table 12), NGC 6383 (table14) and NGC 6530 (table 16)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay all data for this starmeta.ref.urlcharClOpen cluster namemeta.id.parentcharStar? Star number within the cluster (G1)meta.idintnullableONameOther designationmeta.id;meta.maincharn_OName[dd ] Second Balmer Discontinuity (2)meta.notecharVmagVisual magnitude in V filter (3)magphot.mag;em.opt.VfloatE(B-V)? Color excess (4)magphot.color.excessfloatnullablee_E(B-V)? Error in color excessmagstat.errorfloatnullableMODTrue distance modulusmagphot.mag.distModfloate_MODError in true distance modulusmagstat.errorfloatMemberMembership to the cluster (5)meta.code.membercharADAngular distance to the cluster centerarcminpos.angDistancefloatPmembMembership probability%statfloatlogL? Luminositylog(solLum)phys.luminosityfloatnullablee_logL? Error in luminositylog(solLum)stat.errorfloatnullableMass? Stellar masssolMassphys.massfloatnullablee_Mass? Error in stellar masssolMassstat.error;phys.massfloatnullableAge? Age of the starMatime.ageintnullablee_Age? Error in age of the starMastat.error;time.agefloatnullable