J/AJ/153/57ivo://CDS.VizieR/J/AJ/153/57doi:10.26093/cds/vizier.51530057CDSZhai M.Abt H.Zhao G.Li C.2017-07-18T15:15:48Z2017-06-16T16:03:56ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyopen-star-clustersgalaxy-classification-systemsWe present the Galactic characteristics of 154 open clusters using the stellar statistics method with data from the WEBDA database. We find that all clusters in our sample are elongated in shape, which indicates that the spherical clusters are stretched out to be ellipsoid as a function of age (log(age/year)=6.64{--}9.7). By dividing a cluster into a central core and an outer part, we have computed the apparent ellipticities of these two parts respectively. The scale relations between ellipticities and age indicate that the outer parts of open clusters become more elliptical while the central cores remain circular. We suppose that the outer parts become more elliptical because they are more subjected to the external forces, e.g., Galactic differential rotation, while the central cores form a circular shape under the domination of stellar dynamics. We have also performed an analysis of the crucial influence of cluster mass and location on its shape.2017AJ....153...57Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/153/57CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)J/A+A/558/A53 : MW global survey of star clusters. II. (Kharchenko+, 2013)J/A+A/495/807 : Shape parameters for 650 open clusters (Kharchenko+, 2009)J/A+A/477/165 : Nearby open clusters tidal radii and masses (Piskunov+, 2008)J/A+A/468/151 : Nearby open clusters radii and masses (Piskunov+, 2007)http://www.univie.ac.at/webda/ : WEBDAhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/153/57https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/153/57http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/153/57https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/153/57https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/153/57http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/153/57GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/153/57/table1 (Parameters of 154 objects used in this paper)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/153/57/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/153/57/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/153/57/table1?GETtext/xml+votable180.050000true220.03764-66.11530.0055555555555555566/463 1464 1482 1539 1582 1717 1757 1930 2395 2436 2940 3037 3138 3256 3257 3262 3301 3307 3317 3595 3642 4078 4298 4698 6760 12962 13096 13198 13304 13565 13962 14033 14059 14175 14182 14210 14233 14265 14295 14353 14410 14461 14553 14642 14645 15396 15478 15595 15683 15693 20756 20797 21439 21561 21586 21774 22032 22121 22123 22132 22222 22249 22253 22862 22880 22893 22895 22993 23572 23637 23998 24094 24121 24228 24266 24291 24344 24345 24522 28711 28800 28891 28894 28917 29078 29081 29088 29121 29269 29460 29463 29728 30127 30215 30439 31071 31790 31812 31865 37109 37270 37348 37365 37370 37592 37696 37715 37733 37897 37908 37913 37923 37928 37929 37930 37933 38016 38023 38051 38627 39283 39288 39697 39785 39795 39867 39894 41393 41461 41564 41595 41610 41615 41633 41653 41747 41863 41995 42029 42164 42177 42268 42470 42846 43011 43023 43027 43033 43048 43050 47858https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/153/57?format=asciiOpticaldefaultJ/AJ/153/57/table1Parameters of 154 objects used in this paperSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCluster name (1)meta.id;meta.maincharGLONGalactic longitude (l) (1)degpos.galactic.lonGLATGalactic latitude (b) (1)degpos.galactic.latlogAge[6.64/9.7] Logarithm of the cluster age (1)log(yr)time.agefloatDist[150/5071] Distance of the cluster from Sun (1)pcpos.distance;pos.heliocentricintlogM[1/4.2]? Logarithm of the cluster masslog(solMass)phys.massfloatnullableRgc[5.5/13.1] Distance of the cluster from the Galactic center (d_cen_)kpcpos.distancefloatZgc[1/780] Galactocentric vertical distance (H) (2)pcpos.cartesian.z;pos.galacticfloatNc[20/1237] Total number of member stars of each clustermeta.numberinte[0.017/0.65] Cluster ellipticity (e_all_)src.ellipticityfloate_e[0.027/0.47] 1{sigma} Uncertainty for e ({sigma}_all_)stat.errorfloate-out[0.013/0.545]? Outer cluster ellipticity (e_out_)src.ellipticityfloatnullablee_e-out[0.021/0.21]? 1{sigma} uncertainty for e-out ({sigma}_out_)stat.errorfloatnullablee-in[0.003/0.5]? Inner cluster ellipticity (e_in_)src.ellipticityfloatnullablee_e-in[0.03/0.42]? 1{sigma} uncertainty for e-in ({sigma}_in_)stat.errorfloatnullableq[0.2/44.8] Orientation of open cluster (3)degpos.posAngfloatWEBDAData from WEBDA (http://www.univie.ac.at/webda/)meta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed