J/A+A/702/A48ivo://CDS.VizieR/J/A+A/702/A48doi:10.26093/cds/vizier/bc-ny/leiCDSLiu G.Zhang Y.Zhong J.Qin S.Jiang Y.Chen L.2026-08-03T06:58:28Z2025-11-23T09:41:36ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyopen-star-clustersvisible-astronomyBinary clusters (BCs) provide valuable observational constraints on the formation, early evolution, and dynamical interactions of star clusters. Their spatial and kinematic associations offer unique insights into the hierarchical star formation process and tidal interactions within the Galactic disk. We aim to identify and classify BCs using high-precision astrometric and kinematic data, and to investigate their physical properties, mutual gravitational interactions, and formation rates. We used a comprehensive star cluster catalog that contains 4084 high-quality clusters. Based on spatial and kinematic proximity, we identified 400 cluster pairs involving 686 unique clusters. These pairs were classified into three types: primordial BCs, systems formed through tidal capture or resonant trapping, and hyperbolic encounter pairs. For each system, we calculated the tidal factor to quantify the strength of mutual tidal interaction. Additionally, we constructed multi-cluster systems by identifying transitive connections among cluster pairs. Among the 400 identified cluster pairs, nearly 60.8% (243 pairs) are probably primordial BCs, exhibiting both similar ages and motions. This supports a scenario where they formed together in the same giant molecular cloud. We find that 82.5% of the cluster pairs have strong mutual tidal forces. In addition, 278 star clusters are identified as members of 82 multi-cluster systems, including 27 newly reported groups. Cross-matching with the literature confirms the recovery of previously reported systems and leads to the discovery of 268 new cluster pairs. In our sample, about 16.8% of star clusters are involved in some type of interaction with another cluster, and 9.94% of star clusters are likely born in primordial BCs. Our results provide a comprehensive, homogeneously identified sample of Galactic BCs. The high fraction of primordial BCs and their mutual tidal interaction suggest that cluster formation in pairs is a main outcome of star formation. This work offers new observational constraints on the formation and dynamical evolution of multiple star cluster systems.2025A&A...702A..48Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A48CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/A+A/673/A114 : Improving the open cluster census. II. (Hunt+, 2023)J/A+A/686/A42 : Improving the open cluster census. III. (Hunt+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/702/A48https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/702/A48http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/702/A48https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/702/A48https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/702/A48http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/702/A48GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/702/A48/table3 (Multiple system candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A48/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A48/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A48/table3?GETtext/xml+votable180.050000true84.78-1.930.0055555555555555566/862 881 1025 1031 1114 1199 1277 1338 1415 1433 1445 1451 1457 1630 1794 1801 1931-1932 1935 2940 2986 3005 3057 3059-3060 3283 3369 3373 3626 3695 3717 3743 3783 3854-3855 3877-3878 14015 14175 14227 14266 14290 14346 14523 14571 14622 14629 14640 14645-14646 14689 14791 14812 14878 15390 15408 15429 15437 15451 15570 15577 15659 15662 15664 15667 15670 15672-15673 15675 15677 15682-15683 15686 15712 15747 15760 15764-15765 20741 20787 20818-20819 20822 20849 20853 20859-20861 20939 21313 21368 21438 21638 21641 21643 21646 21674 22035 22038 22136 22246 22249 22253 22809 22829 22854 22857 22859-22860 22863 22880 22892-22893 22895 22922 22993 23003 23007 23281 23457 23549 23552 23573 23613 23679 23685 23697 23717 23763 23769 23958 23977 23993 23995 24324 24333 28808-28810 28836-28838 29071 29089 29092 29095 29097 29102 29456-29457 29459-29460 29462 30359 30366 30439 32093 32126 36956 36963 37172 37188 37208 37749-37750 37757 37859 37862 37866 37868 37882 37886 37895 37897 37923 37926 38016-38018 38024 38026 39181 39201 39216 39237 39248 39254 39259 39267 39273-39274 39276 39280 39282-39283 39290 39294 39297 39314 39330 39355 39388 39723 39739 39832 39860 39865 39867 39871 39886 41127 41130 41152 41382 41482 41507 41510 41536 41630 41644 41652-41653 41662 41682 41696 41699 41704 41768 41770 42369-42370 42376 42394 42405 42415-42417 42483 42486 42598 42611 42618 42656 42686 42730 42983 42988 43002 43011 43025 43027 43293 43402 43529 44360 44378 44389https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/702/A48?format=asciiOpticaldefaultJ/A+A/702/A48/table2Binary cluster candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPair[1/400] Pair identification numbermeta.idintIDHR24[1/7166] Cluster ID from Hunt et al. (2024, Cat. J/A+A/686/A42)meta.idintClusterStar cluster namemeta.id;meta.maincharsep3DThe 3D separation between clusters,pcpos.distance;phys.sizefloatDvtTangential velocity differencekm/sphys.veloc;arith.difffloatDv3d? 3D velocity differences between clusterskm/sphys.veloc;arith.difffloatnullableDageAge difference of the pair clustersMyrtime.age;arith.difffloatlogtCluster age from isochrone fittinglog(yr)time.agefloatDMDistance modulus from isochrone fittingmagphot.mag.distModfloatE(B-V)Reddening from isochrone fittingmagphot.color.excessfloatTypePair classificationsrc.classcharoverlapPrevious references (1)meta.refcharJ/A+A/702/A48/table3Multiple system candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroup[1/82] Group identification numbermeta.idintPair[1/400] Pair identification numbermeta.idintIDHR24[1/7163] Cluster ID (1)meta.idint_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decindexedClusterCluster namemeta.id;meta.maincharRA_ICRSRight Ascension (ICRS) at Ep=2016.0 (1)degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2016.0 (1)degpos.eq.dec;meta.mainPlxParallax (1)maspos.parallaxfloatpmRAProper motion in RA*cos(Dec) (1)mas/yrpos.pm;pos.eq.rafloatpmDEProper motion in Dec (1)mas/yrpos.pm;pos.eq.decfloatRV? Radial velocity (1)km/smeta.idfloatnullablelogtCluster age from isochrone fittingtime.agefloatDMDistance modulus from isochrone fittingmagphot.mag.distModfloatE(B-V)Reddening from isochrone fittingmagphot.color.excessfloat