J/A+A/708/A238ivo://CDS.VizieR/J/A+A/708/A238CDSLi Y.Hu Q.Cai Y.Dai Y.Qin M.Luo Y.2026-05-04T07:43:19Z2026-04-09T18:33:40ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyopen-star-clustersgalaxy-classification-systemsvisible-astronomyOpen clusters (OCs) usually evolve gradually as the number of their members changes, which can be manifested in their morphological characteristics. Therefore, the morphological study of OCs lays the foundation for a better understanding of their formation and evolutionary processes. We aim to investigate the morphological stability of 1490 OCs and further explore the potential change of morphological stability of the OCs at different spatial positions, using the OC catalog from the literature. We delineate the two-dimensional (2D) morphology of OCs quantitatively in the projection perpendicular to the Galactic disk plane by the rose diagram and analyze the slope changes between the morphological stabilities (Score/Souter and Ncore/Nouter) and the number of members (N) within tidal radii to investigate the influence of the external environment on the OCs at different spatial positions. We define for the first time a new morphological stability parameter Ncore/Nouter, a ratio of member numbers between cluster core and outer areas within tidal radii, which has a significant positive correlation against N, with a slope of 1.140+/-0.039, significantly steeper than the 0.720+/-0.026 measured for Score/Souter . This demonstrates that the stellar density in the core is a more sensitive tracer for morphological stability than geometry. Spatially, the radial sample OCs have larger slopes of Ncore/Nouter and Score/Souter against N, with 1.083+/-0.116 and 0.733+/-0.080, respectively, whereas those in the tangential direction 1.013+/-0.110 and 0.529+/-0.075, respectively, which means that the impact on sample OCs from tidal forces directed toward the Galactic center is possibly stronger than that from the shear force caused by the differential rotation of the Galactic disk. Moreover, the sample OCs within 90{deg} of the Galactic center, closer to the bar, exhibit slopes below 0.6 of Score /Souter against N, indicating heightened external perturbations and diminished stability. But the opposite is true for the side greater than 90{deg}. Thus, this illustrates that the influence of the external environment on our sample OCs is asymmetrical. Besides, the sample OCs younger than 30Myr display a shallow slope of 0.751+/-0.166, with those older than 800Myr (1.442+/-0.128), reflecting that young OCs likely endure both internal disruptions, such as early dynamical heating weakening core binding and more severe external disturbances, compared to older OCs. The morphological stability of OCs is not only determined by their gravitational binding, but also strongly modulated by the external environment in which they are located.2026A&A...708A.238Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A238CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A238https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A238http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A238https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/708/A238https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/708/A238http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/708/A238GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/708/A238/table1 (Complete catalog of parameters for 1490 OCs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A238/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A238/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A238/table1?GETtext/xml+votable180.050000true301.23-10.510.0055555555555555565/764-765 814 826 3657 3661 5204 7555 7561 9333 9483 10552 10594 10754 10758 6/463 1072 1101 1117 1119 1218 1267 1276-1277 1283 1285 1287 1289 1297-1298 1302 1308 1317-1318 1323 1325 1332 1335 1339 1347 1351 1383 1385-1386 1423 1445-1446 1451-1452 1455 1457 1461-1462 1464 1481-1482 1486 1509 1514 1539 1582 1650 1653 1661-1662 1717-1718 1755 1757 1781-1783 1789 1794 1801-1802 1807 1825 1839-1840 1853 1890 1923 1930 1948 1953 1970 2395 2436 2517 2807 2902 2940 2942 2994 3004 3011 3015 3028 3034-3035 3038 3040 3043 3045-3047 3050 3052 3054-3055 3065-3067 3091 3097 3110 3136 3142 3145 3147 3149 3153 3168 3170 3186 3201 3227 3230 3254 3261-3262 3274 3276-3277 3280 3289 3296 3298 3301 3308-3309 3317 3329 3331 3335 3362 3364 3384 3481 3493 3584 3593 3596 3598 3601 3604 3606 3608 3610-3611 3613 3615 3619 3621-3623 3626-3627 3631-3633 3636 3638 3640 3642 3644-3645 3649 3659-3660 3662 3674 3680 3684 3687 3712 3714-3715 3718 3721-3723 3729 3743 3752 3783 3796 3879 3974 4078 4298 4698 6149 6307 6760 6817 6881 6894 12824 12941 12943 12955 12962-12963 12972 12975 12984-12985 12990 12995 13040 13048 13050 13052 13055 13096 13198 13225 13266 13286 13291 13304 13309 13559 13746 13874 13952 13962 13982 13989 13992 13994 13996 14013-14014 14033 14046 14065 14070 14078 14094 14098 14103 14126 14129 14134 14162 14175 14182 14206 14210 14221 14223 14225 14229 14237-14238 14242 14246 14251 14253-14255 14258-14259 14262-14264 14267 14270 14280 14282 14285-14286 14288 14295 14298 14300-14301 14303 14306-14307 14309-14310 14315 14321-14322 14324 14330-14331 14336 14346 14353 14356 14358 14363 14370 14373 14384 14391 14400 14402-14404 14407 14410-14413 14415 14418-14419 14424-14425 14427 14430 14438 14449 14452 14455 14553 14571 14575 14598 14603 14606 14611 14617 14620 14623-14624 14626-14627 14632-14633 14638 14640 14642-14643 14648 14650 14653 14686-14687 14689-14690 14692 14696-14698 14715 14717 14719 14725 14730 14732 14740 14749 14752 14791 14800 14816-14817 14820 14878 15121 15363 15366-15367 15371 15374-15376 15378-15379 15381 15384-15386 15389 15391-15393 15396 15399 15404 15410 15412 15417 15424 15426 15430 15432 15434 15436 15443-15444 15447-15449 15462 15477-15478 15483 15497 15581 15590 15595 15616 15622 15629 15632-15633 15636 15642 15656 15659 15662 15671 15677 15686-15687 15695 15701 15706 15711 15747 15759 15765 15827-15828 16490 20562 20745 20797 20814-20815 20821-20823 20825 20828 20833 20849 20853-20854 20903 20940 20951 20957 20966 20989 21267 21337-21338 21351 21369 21438 21450 21456 21504 21506 21509-21510 21513-21514 21517 21519-21520 21522-21523 21529 21531 21538 21540 21549-21550 21552 21557 21560-21561 21567 21584 21586 21602-21603 21632-21633 21643-21644 21647 21656-21658 21670 21680 21682 21687 21689 21691 21693-21694 21697 21719 21741 21774 22018 22021 22032 22037-22038 22048 22053 22058 22065-22066 22084 22089 22091 22094 22097-22098 22107 22112 22121 22123 22130 22134 22146 22161-22162 22183 22209-22211 22215-22216 22219 22224 22239 22245-22246 22249 22253 22305 22311 22314 22408 22433 22499 22858-22859 22871 22895 23410 23580 23583-23584 23620-23622 23626 23632-23633 23637-23638 23641 23645-23646 23656 23663 23665-23666 23677 23684 23696 23717 23745 23761 23765 23768-23769 23797 23801 23807 23840 23852 23906 23936-23938 23952 23976 23979-23980 23994 24032 24057 24121 24130 24228 24291 24326 24329 24333 24344-24345 24361 24376 24378 24387 24461 24465 24470 24476 24491 24502 24510 24522 24527 24539 24544 24553 28709 28711 28715-28716 28745 28800 28802 28806-28807 28809-28810 28812 28818 28822-28825 28830 28838 28868 28874 28876 28879 28889 28891 28900-28901 28913 28916 28922 28976 28997 29032 29035 29066 29081-29082 29088 29092 29095 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41381 41436 41444 41455 41461 41466-41467 41552 41557-41559 41577-41578 41582 41591 41594-41595 41599 41613 41620-41622 41629 41633 41638 41643 41646 41648-41649 41652-41654 41670 41672-41673 41675-41676 41678 41682 41688 41690-41692 41697 41699 41701 41704 41709-41711 41740-41741 41747 41753-41754 41762 41765 41768 41770-41771 41774-41775 41788-41789 41799 41808-41809 41814 41816 41829 41831 41834 41846 41856 41858 41863 41873-41874 41878 41893 41922 41995 42127 42135 42150-42151 42153-42157 42159 42163-42166 42170-42172 42174 42177 42192 42197 42201-42203 42206-42207 42213-42214 42216-42218 42224-42225 42227 42230 42268 42274 42303 42336 42346 42351 42353 42363-42365 42367 42374 42380 42383-42384 42387 42390 42392 42394 42396 42399-42400 42402 42415 42417 42420 42432-42433 42435 42437 42450 42452 42456 42458 42464 42469-42470 42472 42486 42496 42500 42503 42516 42583 42836 42846 42850 43012 43021-43022 43024 43026-43027 43036 43040-43041 43046-43048 43050 43059 43062 43140 43218 43301 43450 47621 47784 49099https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/708/A238?format=asciiOpticaldefaultJ/A+A/708/A238/table1Complete catalog of parameters for 1490 OCsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCluster namemeta.id;meta.maincharRA_ICRSRight ascension (ICRS)degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS)degpos.eq.dec;meta.mainRtMean of the tidal radiuspcphys.size.radius;stat.meanfloate_RtMean of the tidal radius errorpcstat.errorfloatRcoreCore radius obtained by rose diagram methodphys.size.radius;meta.modelledfloate_RcoreCore radius obtained by rose diagram method errorstat.errorfloatNNumber of member stars within the tidal radius of each OCmeta.numberfloate_NNumber of member stars within the tidal radius of each OC errorstat.errorfloatScoreArea within the core region of each OC, {pi}Rcore^2^phys.angSizefloate_ScoreArea within the core region of each OC errorstat.errorfloatSouterArea within the outer region of each OC, sum of all areas in the sectors minus the core areaphys.angSizefloate_SouterArea within the outer region of each OC errorstat.errorfloatNcoreNumber of member stars in the core region of each OCmeta.numberfloate_NcoreNumber of member stars in the core region of each OC errorstat.errorfloatNouterNumber of member stars in the outer region of each OCmeta.numberfloate_NouterNumber of member stars in the outer region of each OC errorstat.errorfloatSimbadNameSimbad column added by the CDSmeta.idcharnullable