J/MNRAS/508/2370ivo://CDS.VizieR/J/MNRAS/508/2370doi:10.26093/cds/vizier.75082370CDSQuintana A.L.Wright N.J.2024-09-20T20:13:45Z2021-10-22T09:13:47ZCDS support team

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

cds-question@unistra.frvisible-astronomytrigonometric-parallaxastrometryproper-motionsstellar-agesstellar-distanceob-starsOB associations play an important role in Galactic evolution, though their origins and dynamics remain poorly studied, with only a small number of systems analysed in detail. In this paper we revisit the existence and membership of the Cygnus OB associations. We find that of the historical OB associations only Cyg OB2 and OB3 stand out as real groups. We search for new OB stars using a combination of photometry, astrometry, evolutionary models and an SED fitting process, identifying 4680 probable OB stars with a reliability of >90%. From this sample we search for OB associations using a new and flexible clustering technique, identifying 6 new OB associations. Two of these are similar to the associations Cyg OB2 and OB3, though the others bear no relationship to any existing systems. We characterize the properties of the new associations, including their velocity dispersions and total stellar masses, all of which are consistent with typical values for OB associations. We search for evidence of expansion and find that all are expanding, albeit anistropically, with stronger and more significant expansion in the direction of Galactic longitude. We also identify two large-scale (160pc and 25km/s) kinematic expansion patterns across the Cygnus region, each including three of our new associations, and attribute this to the effects of feedback from a previous generation of stars. This work highlights the need to revisit the existence and membership of the historical OB associations, if they are to be used to study their properties and dynamics.2021MNRAS.508.2370Qhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/508/2370CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/350 : Gaia EDR3 (Gaia Collaboration, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/508/2370https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/508/2370http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/508/2370https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/508/2370https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/508/2370http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/508/2370GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/508/2370/cyg (Positional, astrometric and SED-fitted parameters for the 4680 probable OB stars (corrected version, 24-Jan-2022))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/508/2370/cyg?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/508/2370/cyg?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/508/2370/cyg?GETtext/xml+votable180.050000true300.20656535.794161940.0055555555555555564/914-915 5/3651 3654-3655 3666-3667 3672-3674 3684-3685 6/14549 14601 14603 14680 14682 14700-14702 14720-14721 14724-14726 14784-14786 14788https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/508/2370?format=asciiOpticaldefaultJ/MNRAS/508/2370/cygPositional, astrometric and SED-fitted parameters for the 4680 probable OB stars (corrected version, 24-Jan-2022)logMassMedian logarithm of the SED-fitted masslog(solMass)phys.massfloatb_logMass16th percentile logarithm of the SED-fitted mass from the posterior distributionlog(solMass)phys.massfloatB_logMass84th percentile logarithm of the SED-fitted mass from the posterior distributionlog(solMass)phys.massfloatb_AV16th percentile of the extinction in the V-bandmagphys.absorptionfloatB_AV84th percentile of the extinction in the V-bandmagphys.absorptionfloatDistMedian SED-fitted distancepcpos.distanceintb_Dist16th percentile SED-fitted distance from the posterior distributionpcpos.distanceintB_Dist84th percentile SED-fitted distance from the posterior distributionpcpos.distanceintGroupGroup assigned to each star. If set to N, the star belongs to no groupmeta.idchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaEDR3Gaia EDR3 source identification numbermeta.id;meta.mainRA_ICRSBarycentric right ascension of the source (ICRS) at Ep=2016.0 (ra)degpos.eq.ra;meta.mainDE_ICRSBarycentric right ascension of the source (ICRS) at Ep=2016.0 (dec)degpos.eq.dec;meta.mainPlxAbsolute stellar parallax of the source at the Ep=2016.0maspos.parallaxfloate_PlxStandard error of the stellar parallax at Ep=2016.0masstat.error;pos.parallaxfloatpmRAProper motion in right ascension pmRA*cosDE of the source in ICRS at Ep=2016.0mas/yrpos.pm;pos.eq.rafloate_pmRAStandard error of proper motion in right ascension directionmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in declination direction of the source in ICRS at Ep=2016.0mas/yrpos.pm;pos.eq.decfloate_pmDEStandard error of proper motion in declination directionmas/yrstat.error;pos.pm;pos.eq.decfloatpmlProper motion in Galactic longitude direction at Ep=2016.0mas/yrpos.pmfloate_pmlStandard error of proper motion in Galactic longitude directionmas/yrstat.errorfloatpmbProper motion in Galactic latitude direction at Ep=2016.0mas/yrpos.pmfloate_pmbStandard error of proper motion in Galactic latitude directionmas/yrstat.errorfloatlogTeffMedian logarithm of the SED-fitted effective temperaturelog(K)phys.temperature.effective;stat.medianfloatb_logTeff16th percentile logarithm of the SED-fitted effective temperature from the posterior distributionlog(K)phys.temperature.effectivefloatB_logTeff84th percentile logarithm of the SED-fitted effective temperature from the posterior distributionlog(K)phys.temperature.effectivefloatlogLumMedian logarithm of the SED-fitted luminositylog(solLum)phys.luminosityfloatb_logLum16th percentile logarithm of the SED-fitted luminosity from the posterior distributionlog(solLum)phys.luminosityfloatB_logLum84th percentile logarithm of the SED-fitted luminosity from the posterior distributionlog(solLum)phys.luminosityfloatAVMedian extinction in the V-bandmagphys.absorptionfloat