J/MNRAS/477/2976ivo://CDS.VizieR/J/MNRAS/477/2976doi:10.26093/cds/vizier.74772976CDSNegueruela I.Monguio M.Marco A.Tabernero H.M.Gonzalez-fernandez C.,Dorda R.2024-08-18T20:19:09Z2021-08-20T13:11:02ZCDS support team

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

cds-question@unistra.fropen-star-clustersstellar-populationsvisible-astronomybroad-band-photometrymorgan-keenan-classificationThe heavily obscured open cluster Berkeley 51 shows characteristics typical of young massive clusters, even though the few previous studies have suggested older ages. We combine optical (UBV) and 2MASS photometry of the cluster field with multi-object and long-slit optical spectroscopy for a large sample of stars. We apply classical photometric analysis techniques to determine the reddening to the cluster, and then derive cluster parameters via isochrone fitting. We find a large population of B-type stars, with a main-sequence turn-off at B3 V, as well as a large number of supergiants with spectral types ranging from F to M. We use intermediate-resolution spectra of the evolved cool stars to derive their stellar parameters and find an essentially solar iron abundance. Under the plausible assumption that our photometry reaches stars still close to the zero-age main sequence, the cluster is located at d=~5.5kpc and has an age of ~60Ma, though a slightly younger and more distant cluster cannot be ruled out. Despite the apparent good fit of isochrones, evolved stars seem to reside in positions of the colour-magnitude diagram far away from the locations where stellar tracks predict helium burning to occur. Of particular interest is the presence of four yellow supergiants, two on the ascending branch and two others close to or inside the instability strip.2018MNRAS.477.2976Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/477/2976CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/477/2976https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/477/2976http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/477/2976https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/477/2976https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/477/2976http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/477/2976GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/477/2976/tableb1 (Coordinates, UBV photometry, 2MASS identification and 2MASS JHKS photometry for all stars in the field of Berkeley 51)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/2976/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/2976/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/2976/tableb1?GETtext/xml+votable180.050000true302.95412534.35402780.005555555555555556Cone search capability for table J/MNRAS/477/2976/table3 (*Stellar parameters for cool stars in the field of Be 51.)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/2976/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/2976/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/2976/table3?GETtext/xml+votable180.050000true302.982368934.40302030.0055555555555555566/146068.650015785639275e-20 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/477/2976?format=asciiOpticaldefaultJ/MNRAS/477/2976/tableb1Coordinates, UBV photometry, 2MASS identification and 2MASS JHKS photometry for all stars in the field of Berkeley 51e_Hmag? rms uncertainty on Hmagmagstat.error;phot.magfloatnullableKsmag? 2MASS Ks magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag? rms uncertainty on Ksmagmagstat.error;phot.magfloatnullableFlag2MASS quality flagsmeta.code.errorcharmoreindicates more data in tables 3 and/or 4meta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainName[1/285] Star identification numbermeta.id;meta.mainintprimaryVmagV magnitudemagphot.mag;em.opt.Vfloate_Vmagrms uncertainty on Vmagmagstat.error;phot.magfloatB-VB-V colour indexmagphot.color;em.opt.B;em.opt.Vfloate_B-Vrms uncertainty on B-Vmagstat.error;phot.color;em.opt.BfloatU-BU-B colour indexmagphot.color;em.opt.U;em.opt.Bfloate_U-Brms uncertainty on U-Bmagstat.error;phot.color;em.opt.UfloatnNumber of measurements in UBVmeta.numberint2MASS2MASS designation (HHMMSSss+DDMMSSs)meta.idcharJmag? 2MASS J magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? rms uncertainty on Jmagmagstat.error;phot.magfloatnullableHmag? 2MASS H magnitudemagphot.mag;em.IR.HfloatnullableJ/MNRAS/477/2976/table3*Stellar parameters for cool stars in the field of Be 51.SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identification numbermeta.id;meta.mainintSpTypeSpectral type (1)src.spTypecharDateObservation datetime.epoch;obsnullableTeff? Effective temperatureKphys.temperature.effectiveintnullablee_Teff? rms uncertainty on TeffKstat.error;phys.temperature.effectiveintnullablelogg? Surface gravitylog(cm.s**-2)phys.gravityfloatnullable[M/H]? Metallicityphys.abund.Zfloatnullablee_[M/H]? rms uncertainty on [M/H]stat.error;phys.abundfloatnullablevt? Microturbulent velocitykm/sphys.velocfloatnullableMARCS? MARCS gridsolMassmeta.codeintnullablevhelHeliocentric velocitykm/sphys.veloc;pos.heliocentricintvLSRLSR velocitykm/sphys.veloc;pos.lsrint_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/MNRAS/477/2976/table4Intrinsic parameters for all very likely photometric members, ordered by dereddened magnituderecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identification numbermeta.id;meta.mainintSpTypePhPhotometric spectral type (1)src.spTypecharSpTypeSpectral type (when available) (2)src.spTypecharE(B-V)Reddeningmagphot.color.excessfloatn_E(B-V)[bc] Note on E(B-V) (3)meta.notechar