J/AJ/168/206ivo://CDS.VizieR/J/AJ/168/206doi:10.26093/cds/vizier.51680206CDSTregoning K.R.Andrews J.J.Agueros M.A.Cargile P.A.Chaname J.,Curtis J.L.Schuler S.C.2025-08-01T20:09:58Z2025-07-03T15:12:02ZCDS support team

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

cds-question@unistra.fropen-star-clustersastrometryradial-velocityvisible-astronomyspectroscopymetallicityproper-motionstrigonometric-parallaxstellar-radiistellar-agesstellar-massesstellar-associationsThe application of clustering algorithms to the Gaia astrometric catalog has revolutionized our census of stellar populations in the milky Way, including the discovery of many new dispersed structures. We focus on one such structure, Theia 456 (COIN-Gaia-13), a loosely bound collection of ~320 stars spanning ~120pc that has previously been shown to exhibit kinematic, chemical, and gyrochronal coherency, indicating a common origin. We obtain follow-up radial velocities and supplement these with Gaia astrometry to perform an in-depth dynamical analysis of Theia 456. By integrating stellar orbits through a Milky Way potential, we find the currently dispersed structure coalesced into a small cluster in the past. Via Bayesian modeling, we derive a kinematic age of 245+/-3Myr (statistical), a half-mass-radius of 9+/-2pc, and an initial one-dimensional velocity dispersion of 0.14+/-0.02km/s. Our results are entirely independent of model isochrones, details of stellar evolution, and internal cluster dynamics, and the statistical precision in our age derivation rivals that of the most precise age-dating techniques known today, though our imperfect knowledge of the Milky Way potential and simple spherical model for Theia 456 at birth add additional uncertainties. Using posterior predictive checking, we confirm these results are robust under reasonable variations to the Milky Way potential. Such low-density structures that are disrupted by the Galactic tides before virializing may be ubiquitous, signifying that Theia 456 is a valuable benchmark for studying the dynamical history of stellar populations in the Milky Way.2024AJ....168..206Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/168/206CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)V/164 : LAMOST DR5 catalogs (Luo+, 2019)J/ApJ/799/136 : IN-SYNC. II. Cand. young stars in NGC 1333 (Foster+, 2015)J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)J/MNRAS/473/849 : Mass segregation in Galactic stellar clusters (Dib+, 2018)J/A+A/624/A126 : New open clusters in Perseus direction (Cantat-Gaudin+, 2019)J/AJ/158/122 : Local structure & star formation hist. of MW (Kounkel+, 2019)J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019)J/A+A/633/A99 : GaiaDR2 open clusters in Milky Way. II (Cantat-Gaudin+, 2020)J/ApJ/904/140 : Ruprecht 147 members & rot. data: 5 other cl. (Curtis+, 2020)J/AJ/160/279 : Untangling the Gal. II. Within 3kpc (Kounkel+, 2020)J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)J/ApJ/904/196 : Stellar parameters of a Young Stellar Snake (Tian, 2020)J/AJ/159/166 : Membership & data of moving groups: Gaia (Ujjwal+, 2020)J/MNRAS/495/663 : Gaia DR2 OB associations (Ward+, 2020)J/A+A/646/A104 : Improving the open cluster census. I. (Hunt+, 2021)J/ApJ/917/23 : SPYGLASS. I. Mapping young stellar structures (Kerr+, 2021)J/A+A/645/A84 : Coronae of nearby star clusters (Meingast+, 2021)J/MNRAS/505/5978 : Gaia EDR3 view on Gal. globular clusters (Vasiliev+, 2021)J/AJ/163/275 : Theia 456; a stellar stream in MW disk (Andrews+, 2022)J/A+A/661/A118 : 628 new open clusters found: OCfinder (Castro-Ginard+, 2022)J/A+A/660/A4 : Gaia EDR3 new Galactic open clusters (Hao+, 2022)J/ApJS/262/7 : 886 nearby star clusters (He+, 2022)J/ApJS/266/36 : Open star clusters within 5kpc in Gaia DR3 (Chi+, 2023)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/AJ/168/206https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/168/206http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/168/206https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/168/206https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/168/206http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/168/206GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/168/206/table2 (Theia 456 catalog, phase-space and astrometry)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/168/206/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/168/206/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/168/206/table2?GETtext/xml+votable180.050000true84.4340.330.0055555555555555565/337 339 345 347 370 376 462 483-484 6/1353 1355 1360 1362 1368 1370 1385 1387 1392 1469 1471 1473-1478 1484 1512 1809 1813 1815 1817-1822 1837 1839-1840 1842-1843 1846 1925-1927 1944 1956 1958 1968 24557 24559 24570https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/168/206?format=asciiOpticaldefaultJ/AJ/168/206/table2Theia 456 catalog, phase-space and astrometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDGaia DR3 identifiermeta.id;meta.mainRAJ2000[65/88] Gaia DR3 Right Ascension (J2000)degpos.eq.ra;meta.mainFe/H[-0.4/0.2]? Iron Abundance relative to Sun derived via MINESweeper (1)log(Sun)phys.abund.Fefloatnullablee_Fe/H[3e-3/0.4]? Lower Quartile Error (16%) on Fe/H (1)log(Sun)stat.error;stat.min;phys.abund.FefloatnullableE_Fe/H[4e-3/0.2]? Upper Quartile Error (84%) on Fe/H (1)log(Sun)stat.error;stat.max;phys.abund.Fefloatnullablea/Fe[-0.2/0.3]? Alpha Process Elemental Abundance relative to Sun derived via MINESweeper (1)log(Sun)phys.abundfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchare_RAJ2000[0.01/0.2] Error in RAdegdegstat.error;pos.eq.rafloatDEJ2000[37/56] Gaia DR3 Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000[0.01/0.1] Error in DEdegdegstat.error;pos.eq.decfloatplx[1.7/2.3] Gaia DR3 Parallaxmaspos.parallax.trigfloate_plx[0.01/0.2] Error in plxmasstat.error;pos.parallax.trigfloatpmRA[-5.4/-3.2] Gaia DR3 Proper Motion in RA*cos(Declination), pmRA*cos (DEdeg)mas/yrpos.pm;pos.eq.rafloate_pmRA[0.01/0.3] Error in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDE[-2.1/-0.5] Gaia DR3 Proper Motion in Declinationmas/yrpos.pm;pos.eq.decfloate_pmDE[0.01/0.2] Error in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatRVel[-35/14]? Gaia DR3 Radial Velocitykm/sspect.dopplerVelocfloatnullablee_RVel[0.01/19]? Error in RVelkm/sstat.error;spect.dopplerVelocfloatnullableSNR[0.5/174]? SNR of MMT-Hectochelle spectrastat.snrfloatnullableVrad[-17/-11]? Radial Velocity derived via MINESweeper (1)km/sspect.dopplerVelocfloatnullablee_Vrad[0.01/5.4]? Lower Quartile Error (16%) on Vrad (1)km/sstat.error;stat.min;spect.dopplerVelocfloatnullableA22Display data from Andrews+ 2022, J/AJ/163/275meta.ref.urlcharE_Vrad[0.01/5.3]? Upper Quartile Error (84%) on Vrad (1)km/sstat.error;stat.max;spect.dopplerVelocfloatnullableVrot[6e-5/50]? Rotational Velocity derived via MINESweeper (1)km/sphys.veloc.rotatdoublenullablee_Vrot[0/7.6]? Lower Quartile Error (16%) on Vrot (1)km/sstat.error;stat.min;phys.veloc.rotatdoublenullableE_Vrot[0/6.1]? Upper Quartile Error (84%) on Vrot (1)km/sstat.error;stat.max;phys.veloc.rotatdoublenullableDist[434/598]? Distance derived via MINESweeper (1)pcpos.distancefloatnullablee_Dist[0.1/17]? Lower Quartile Error (16%) on Dist (1)pcstat.error;stat.min;pos.distancefloatnullableE_Dist[0.2/21]? Upper Quartile Error (84%) on Dist (1)pcstat.error;stat.max;pos.distancefloatnullableAv[0.01/1.5]? V Band Extinction derived via MINESweeper (1)magphys.absorption;em.opt.Vfloatnullablee_Av[0/0.2]? Lower Quartile Error (16%) on Av (1)magstat.error;stat.min;phys.absorptionfloatnullableE_Av[0/0.2]? Upper Quartile Error (84%) on V Av (1)magstat.error;stat.max;phys.absorptionfloatnullableTeff[3616/7760]? Effective Temperature derived via MINESweeper (1)Kphys.temperature.effectiveintnullablee_Teff[2/65]? Lower Quartile Error (16%) on Teff (1)Kstat.error;stat.min;phys.temperature.effectiveintnullableE_Teff[2/72]? Upper Quartile Error (84%) on Teff (1)Kstat.error;stat.max;phys.temperature.effectiveintnullablelogg[4.2/4.8]? Log of Surface Gravity derived via MINESweeper (1)log(cm.s**-2)phys.gravityfloatnullablee_logg[1e-3/0.04]? Lower Quartile Error (16%) on logg (1)log(cm.s**-2)stat.error;stat.min;phys.gravityfloatnullableE_logg[2e-3/0.04]? Upper Quartile Error (84%) on logg (1)log(cm.s**-2)stat.error;stat.max;phys.gravityfloatnullablelogRs[-0.3/0.3]? Log of Stellar Radius derived via MINESweeper (1)log(solRad)phys.size.radiusfloatnullablee_logRs[2e-3/0.02]? Lower Quartile Error (16%) on logRs (1)log(solRad)stat.error;stat.min;phys.size.radiusfloatnullableE_logRs[1e-3/0.02]? Upper Quartile Error (84%) on logRs (1)log(solRad)stat.error;stat.max;phys.size.radiusfloatnullablee_a/Fe[0/0.07]? Lower Quartile Error (16%) on a/Fe (1)log(Sun)stat.error;stat.min;phys.abundfloatnullableE_a/Fe[1e-3/0.2]? Upper Quartile Error (84%) on a/Fe (1)log(Sun)stat.error;stat.max;phys.abundfloatnullablelogAge[7/9]? Log of Stellar Age derived via MINESweeper (1)log(yr)time.agefloatnullablee_logAge[1e-3/0.7]? Lower Quartile Error (16%) on logAge (1)log(yr)stat.error;stat.min;time.agefloatnullableE_logAge[2e-3/0.7]? Upper Quartile Error (84%) on logAge (1)log(yr)stat.error;stat.max;time.agefloatnullableMstar[0.5/1.5]? Stellar Mass derived via MINESweeper (1)solMassphys.massfloatnullablee_Mstar[4e-3/0.04]? Lower Quartile Error (16%) on Mstar (1)solMassstat.error;stat.min;phys.massfloatnullableE_Mstar[2e-3/0.02]? Upper Quartile Error (84%) on Mstar (1)solMassstat.error;stat.max;phys.massfloatnullablelogLs[-1.4/0.9]? Log of Stellar Luminosity derived via MINESweeper (1)log(solLum)phys.luminosity;em.opt.Vfloatnullablee_logLs[5e-3/0.05]? Lower Quartile Error (16%) on LogLs (1)log(solLum)stat.error;stat.min;phys.luminosityfloatnullableE_logLs[3e-3/0.05]? Upper Quartile Error (84%) on logLs (1)log(solLum)stat.error;stat.max;phys.luminosityfloatnullableplx2[1.6/2.4]? Parallax derived via MINESweeper (1)maspos.parallaxfloatnullablee_plx2[1e-3/0.1]? Lower Quartile Error (16%) on plx2 (1)masstat.error;stat.min;pos.parallaxfloatnullableE_plx2[6e-4/0.1]? Upper Quartile Error (84%) on plx2 (1)masstat.error;stat.max;pos.parallaxfloatnullablespFlag for stars with MMT-Hectochelle spectra and derived stellar parameters via MINESweeper (True = 43 occurrences) (2)meta.codechar