J/A+A/710/A4ivo://CDS.VizieR/J/A+A/710/A4CDSHu Q.Cai Y.Soubiran C.Dai Y.Li Y.Luo Y.Qin M.2026-05-28T07:56:04Z2026-05-28T08:55:12ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyopen-star-clustersvisible-astronomyOpen clusters (OCs) in our Galaxy can be found in pairs, possibly forming physical binaries, or in groups. These objects offer unique insights into the process of star formation and testify to the dynamical interactions at local and galactic scales. Therefore, building as complete a census as possible is a valuable endeavor. This work is aimed at identifying and characterizing new OC pair candidates that had been overlooked in previous studies. Two recent comprehensive catalogs were cross-matched to identify OCs in the first catalog that had been missing from the second one. From this list, counterparts in the second catalog were searched within a 3D distance of 50 pc. Candidate pairs were then selected by applying constraints on the tangential velocity (TV) difference. An orbital integration was performed to assess gravitational binding. The similarity in terms of the radial velocity (RV) and age was evaluated. We identified seven isolated binary cluster candidates, comprising two likely bound systems with stable orbits over 100 Myr; two pairs with a possible common origin but lacking RV confirmation; and three pairs with significant velocity discrepancies, suggesting they are unbound or in transitional states. We also identified six cluster group candidates, while refining the membership of known complexes such as UBC_672 and NGC_1977, and discovering a new group around FSR_0198. Notably, the UBC_392 group exhibits coherent proper motions but inconsistent RVs and large age spreads, indicating that it is not gravitationally bound. Additionally, we reconciled 15 clusters with discrepant nomenclature between the two catalogs. Multi-catalog integration combined with kinematic and dynamical validation is essential for establishing a complete census of Galactic cluster pairs. Our findings have effectively expanded the known binary cluster sample and provided refined targets for future studies.2026A&A...710A...4Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A4CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/633/A99 : Gaia DR2 open clusters in the Milky Way. IIJ/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/710/A4https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A4http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A4https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A4https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A4http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A4GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/710/A4/table (Parameters of 83 CG20 OCs missing in H&R24)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A4/table?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A4/table?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A4/table?GETtext/xml+votable180.050000true100.76666671.67194440.005555555555555556Cone search capability for table J/A+A/710/A4/tablea (Merged parameters of 32 cluster pairs (tables A1 + A2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A4/tablea?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A4/tablea?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A4/tablea?GETtext/xml+votable180.050000true83.8479167-4.48611110.0055555555555555566/1299 1332 1446 1785 1934 2902 3032 3062 3251 3253 3258 3308 3614 3631 3638 3723 3910 6330 7086 13230 14267 14301-14302 14602 14604 14633 15372 15676 21552 21680 21804 21918 22124 22211 22260 22340 22343 22348 22421 22478 22805 23621 23848 24369 28828 29509-29510 30482 30719 37244 37247 37317 37332 37373 37715 37745 37841 37918 37923 37926 37931 38016 38619 39172 39233 39269 39398 39403 39409-39411 39527 39710 39755 39771 39777 39780 39801 39879 39892 40490 40499 40516 40525 41655 41696 42169 42206 42220 42416 42462 43017 47854https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/710/A4?format=asciiOpticaldefaultJ/A+A/710/A4/tableParameters of 83 CG20 OCs missing in H&R24recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster name in CG20 (1)meta.id;meta.maincharSimbadNameSimbad column added by the CDSmeta.idcharnullableNNumber of member stars from CG20 (1)meta.numberintRAdegMedian right ascension (J2000)degpos.eq.raDEdegMedian declination (J2000)degpos.eq.decplxMedian parallaxmaspos.parallax.trigfloate_plxUncertainty (MAD) of plxmasstat.error;pos.parallaxfloatpmRAMedian proper motion in RAmas/yrpos.pm;pos.eq.rafloate_pmRAUncertainty (MAD) of pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEMedian proper motion in DECmas/yrpos.pm;pos.eq.decfloate_pmDEUncertainty (MAD) of pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatRV? Median radial velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_RV? Uncertainty (MAD) of RVkm/sstat.errorfloatnullablen_RVNumber of members with a RVmeta.noteint_RA(right ascension part)degpos.eq.ra;meta.main_DE(declination part)degpos.eq.dec;meta.mainJ/A+A/710/A4/tableaMerged parameters of 32 cluster pairs (tables A1 + A2)b_logAgeHR24Logarithmic the 16th age from H&R24 (2)log(yr)time.agefloatB_logAgeHR24Logarithmic the 84th age from H&R24 (2)log(yr)time.agefloatSimbadNameSimbad column added by the CDSmeta.idcharnullable_RA(right ascension part)degpos.eq.ra;meta.main_DE(declination part)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCG20Cluster name in CG20 (1)meta.id;meta.maincharClusterHR24Cluster name in H&R24 (2)meta.idcharpmRACG20Median proper motion in RA for CG20 (1)mas/yrpos.pm;pos.eq.rafloate_pmRACG20Uncertainty (MAD) of pmRA for CG20 (1)mas/yrstat.error;pos.pm;pos.eq.rafloatpmRAHR24Proper motion in RA from H&R24 (2)mas/yrpos.pm;pos.eq.rafloate_pmRAHR24Error of pmRA from H&R24 (2)mas/yrstat.error;pos.pm;pos.eq.rafloatpmDECG20Median proper motion in Dec for CG20 (1)mas/yrpos.pm;pos.eq.decfloate_pmDECG20Uncertainty (MAD) of pmDE for CG20 (1)mas/yrstat.error;pos.pm;pos.eq.decfloatpmDEHR24Proper motion in Dec from H&R24 (2)mas/yrpos.pm;pos.eq.decfloate_pmDEHR24Error of pmDE from H&R24 (2)mas/yrstat.error;pos.pm;pos.eq.decfloatplxCG20Median parallax for CG20 (1)maspos.parallax.trigfloate_plxCG20Uncertainty (MAD) of parallax for CG20 (1)masstat.errorfloatplxHR24Parallax from H&R24 (2)maspos.parallax.trigfloate_plxHR24Error of parallax from H&R24 (2)masstat.errorfloatDelta3D3D separation between the two clusterspcpos.distancefloatRVCG20? Median radial velocity for CG20 (1)km/sphys.veloc;pos.heliocentricfloatnullablee_RVCG20? Uncertainty (MAD) of RV for CG20 (1)km/sstat.errorfloatnullableNRVCG20Number of stars with RV for CG20 (1)meta.numberintRVHR24? Radial velocity from H&R24 (2)km/sphys.veloc;pos.heliocentricfloatnullablee_RVHR24? Error of RV from H&R24 (2)km/sstat.errorfloatnullableNRVHR24Number of stars with RV for H&R24 (2)meta.numberintTVCG20Median tangential velocity for CG20 (1)km/sphys.veloc.transversefloate_TVCG20Uncertainty (MAD) of TV for CG20 (1)km/sstat.errorfloatTVHR24Median tangential velocity for H&R24 (2)km/sphys.veloc.transversefloate_TVHR24Uncertainty (MAD) of TV for H&R24 (2)km/sstat.errorfloatlogAgeCG20? Logarithmic age from CG20 (1)log(yr)time.agefloatnullablelogAgeHR24Logarithmic the 50th age from H&R24 (2)log(yr)time.agefloat