J/A+A/679/A122ivo://CDS.VizieR/J/A+A/679/A122doi:10.26093/cds/vizier.36790122CDSViscasillas Vazquez C.Magrini L.Spina L.Tautvaisiene G.,Van der Swaelmen M.Randich S.Sacco G.G.2024-11-06T20:06:13Z2024-05-02T08:32:33ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyopen-star-clustersvisible-astronomyThe survival time of a star cluster depends on its total mass, density, and thus size, as well as on the environment in which it was born and in which lies. Its dynamical evolution is influenced by various factors such as gravitational effects of the Galactic bar, spiral structures, and molecular clouds. Overall, the factors that determine the longevity of a cluster are complex and not fully understood. This study aims to investigate whether open clusters and field stars respond differently to the perturbations that cause radial migration. In particular, we aim to understand the nature of the oldest surviving clusters. We compared the time evolution of the kinematic properties of two Gaia DR3 samples. The first sample is composed of ~40 open clusters and the second one of ~66000 main sequence turn off field stars. Both of the samples are composed of stars selected with the same quality criterion, and they belong to the thin disc, are in a similar metallicity range, are located in the same Galactocentric region [7.5-9kpc], and have ages greater than 1 Gyr. We performed a statistical analysis comparing the properties of the samples of the field stars and of the open clusters. A qualitative comparison of kinematic and orbital properties revealed that clusters younger than 2-3Gyr are more resistant to perturbations than field stars, and they move along quasi-circular orbits. Conversely, clusters older than approximately 3Gyr have more eccentric and inclined orbits than isolated stars in the same age range. Such orbits lead the older clusters to reach higher elevations on the Galactic plane, maximising their probability to survive several more gigayears. A formal statistical analysis revealed that there are differences among the time evolution of most of the kinematic and orbital properties of the field stars and open clusters. However, the comparison between some properties (e.g., V_phi_ and L_Z_) do not reach a sufficient statistical significance. Our results suggest that the oldest surviving clusters are usually more massive and move on orbits with a higher eccentricity. Although they are still reliable tracers of the Galaxy's past composition, they do not reflect the composition of the place where they are currently found. Therefore, we cannot avoid considering kinematic properties when comparing data and models of chemical evolution and also taking into account the intrinsic differences between clusters and isolated stars. To validate the results, new studies that increase the sample of open clusters, especially at older ages, are needed.2023A&A...679A.122Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/679/A122CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/A+A/640/A1 : Portrait Galactic disc (Cantat-Gaudin+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/679/A122https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/679/A122http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/679/A122https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/679/A122https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/679/A122http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/679/A122GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/679/A122/tablea1 (Properties of the open clusters used in this study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/679/A122/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/679/A122/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/679/A122/tablea1?GETtext/xml+votable180.050000true13.801286449.53865330.0055555555555555566/2862 4298 12891 13198 13286 13996 14575 14629 14645 14730 14752 14800 14817 14820 15121 15396 15497 15595 15709 21531 29144 29728 30439 32198 37161 37235 37672 37717 37936 37942 38242 38537 39290 39326 39356 39912 40101 43017https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/679/A122?format=asciiOpticaldefaultJ/A+A/679/A122/tablea1Properties of the open clusters used in this studySimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id;meta.mainchar[M/H]Calibrated metallicity (1)phys.abund.Zfloat[alpha/Fe]Abundance [alpha/Fe] (1)phys.abundfloatAgeAge (2)Gyrtime.agefloatRGCGalactocentric radius (1)pcpos.distance;pos.galactocentricfloateEccentricity (3)src.orbital.eccentricityfloatZmaxMaximun height above the plane (3)kpcpos.cartesian.zfloatVRRadial velocity (3)km/sspect.dopplerVelocfloatVphitangential velocity (3)km/sphys.veloc.transversefloat|VZ|Absolute vertical velocity (3)km/sphys.veloc;pos.cartesian.zfloatJRRadial action (3)kpc.km/sarith.grad;phys.velocfloatJZVertical action (3)kpc.km/sarith.grad;phys.velocfloatLZazimuthal action (3)kpc.km/sphys.angMomentumdoubleNNumber of member stars (2)meta.numberint_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable