J/MNRAS/490/2521ivo://CDS.VizieR/J/MNRAS/490/2521doi:10.26093/cds/vizier.74902521CDSHetem A.Gregorio-Hetem J.2024-08-20T20:13:45Z2019-11-04T08:10:36ZCDS support team

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

cds-question@unistra.fropen-star-clustersproper-motionsWe used fractal statistics to quantify the degree of observed substructures in a sample of 50 embedded clusters and more evolved open clusters (<100Myr) found in different galactic regions. The observed fractal parameters were compared with N-body simulations from the literature, which reproduce star-forming regions under different initial conditions and geometries that are related to the cluster' dynamical evolution. Parallax and proper motion from Gaia-DR2 were used to accurately determine cluster membership by using the Bayesian model and cross-entropy technique. The statistical parameters Q, <m> and <s> were used to compare observed cluster structure with simulations. A low level of substructures (Q<0.8) is found for most of the sample that coincides with simulations of regions showing fractal dimension D~2-3. Few clusters (<20 per cent) have uniform distribution with a radial density profile ({alpha}<2). A comparison of Q with mass segregation ({LAMBDA}MSR) and local density as a function of mass ({SIGMA}LDR) shows the clusters coinciding with models that adopt supervirial initial conditions. The age-crossing time plot indicates that our objects are dynamically young, similar to the unbound associations found in the Milky Way. We conclude that this sample may be expanding very slowly. The flat distribution in the Q-age plot and the absence of trends in the distributions of {LAMBDA}MSR and {SIGMA}LDR against age show that in the first 10 Myr the clusters did not change structurally and seem not to have expanded from a much denser region.2019MNRAS.490.2521Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/490/2521CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/490/2521https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/490/2521http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/490/2521https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/490/2521https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/490/2521http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/490/2521GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/490/2521/table1 (Structural results based on spatial distribution and fractal statistics (P50))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/2521/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/2521/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/2521/table1?GETtext/xml+votable180.050000true78.3144.5840.005555555555555556Cone search capability for table J/MNRAS/490/2521/stars (Proper motions and membership for all clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/2521/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/2521/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/2521/stars?GETtext/xml+votable180.050000true77.996950166744.48110198890.0055555555555555565/113 115-116 118 440 442 784 1174 7177 9307 10417 6/476 478 484-485 487 496-497 500 1439 1480 1482 1695 1714-1715 1719 1725-1727 1772 1774-1775 3092-3093 3095 3101-3102 3140-3142 3144-3146 3148 3150-3151 3172 4681 4685-4687 4690-4691 4694 4700 4702 4709 4720-4721 4723-4724 4726 4728 13279 13962 14367 14389 14410 14432 14642 14644 14646-14648 20756-20757 22021 22249 22252 22858 22880-22881 22893 22895 22904 22906 23637 23639 24338-24339 24342 24344-24345 24348 28716-28717 28722 28728 28812 28890-28891 29095 29113 29269 29271 29440 29442 29512-29513 30437-30439 30445 30450 37225-37227 37240 37242-37243 37313 37316-37317 37328-37329 37721 37785 37787-37788 37790-37791 37809 37812 37839 37923 37926 37933 37938 37944 38023 39233 39237 39239 39867 39907 39930 41582-41583 41633 41635 41677 41696 41747 41750 41832 41834 41856 41994-41995 42017 42203 42376-42377 42470https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/490/2521?format=asciidefaultJ/MNRAS/490/2521/table1Structural results based on spatial distribution and fractal statistics (P50)SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id.parentcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.maine_RAJ2000rms uncertainty on RAdegdegstat.error;pos.eq.rafloatDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000rms uncertainty on DEdegdegstat.error;pos.eq.decfloatpmRAProper motion along RA, pmRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRArms uncertainty on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatNpmTotal number of P50 members identified on the basis on proper motionmeta.numberintRCluster radius (1)pcphys.size.radiusfloate_Rrms uncertainty on Rpcstat.errorfloatnStellar surface density (in stars/pc^2^)pc**-2src.densityfloatrcRadius of the corepcphys.size.radiusfloat<m>Mean edge length that is related to the surface density of the point distributionstat.fit.paramfloat<s>Mean separation of the points in the minimal spanning tree (2)stat.fit.paramfloatQFractal Q parameter (3)stat.fit.paramfloatJ/MNRAS/490/2521/starsProper motions and membership for all clusterse_logAge? Error in agelog(yr)stat.error;time.agefloatnullableMass? MasssolMassphys.massfloatnullablee_Mass? Error in masssolMassstat.error;phys.massfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id.parentchar2MASS2MASS identificationmeta.id;meta.maincharRAJ2000Right ascension (J2000), at Epoch=1989.0pos.eq.ra;meta.mainDEJ2000Declination (J2000), at Epoch=1989.0pos.eq.dec;meta.mainplxParallaxmaspos.parallax.trigfloate_plxError in parallaxmasstat.error;pos.parallaxfloatpmRAProper motion in RA direction, pmRA*cosDEmas/yrpos.pm;pos.eq.radoublee_pmRAError in proper motion in RA directionmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in DEC directionmas/yrpos.pm;pos.eq.decdoublee_pmDEError in proper motion in DEC directionmas/yrstat.error;pos.pm;pos.eq.decfloatJMAGAbsolute J magnitude (MJ0)magphys.magAbsfloate_JMAGError in absolute J magnitudemagstat.errorfloatJ-KAbsolute J-K colourmagphot.color;em.IR.J;em.IR.Kfloate_J-K? Error in absolute J-K colourmagstat.error;phot.color;em.IR.JfloatnullablePmovMembership probabilitystat.probabilityfloatlogAge? Agelog(yr)time.agefloatnullableSigmaLSD? Local surface densitypc**-2phot.flux.density.sbfloatnullableQual[0/2] Quality flag (1)meta.code.qualintSimbadNameSimbad column added by the CDSmeta.idchar