J/A+A/631/A166ivo://CDS.VizieR/J/A+A/631/A166doi:10.26093/cds/vizier.36310166CDSKos J.Bland-Hawthorn J.Asplund M.Buder S.Lewis G.F.Lin J.,Martell S.L.Ness M.K.Sharma S.De Silva G.M.Simpson J.D.,Zucker D.B.Zwitter T.Cotar K.Spina L.2022-11-22T15:21:39Z2019-11-15T08:09:14ZCDS support team

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

cds-question@unistra.fropen-star-clustersproper-motionsvisible-astronomytrigonometric-parallaxradial-velocityThe Orion complex is arguably the most studied star-forming region in the Galaxy. While stars are still being born in the Orion nebula, the oldest part was believed to be no more than 13Myr old. In order to study the full hierarchy of star formation across the Orion complex, we perform a clustering analysis of the Ori OB1a region using new stellar surveys and derive robust ages for each identified stellar aggregate. We use Gaia DR2 parameters supplemented with radial velocities from the GALAH and APOGEE surveys to perform clustering of the Ori OB1a association. Five overdensities are resolved in a six-dimensional parameter space (positions, distance, proper motions, and radial velocity). Most correspond to previously known structures (ASCC 16, 25 Orionis, ASCC 20, ASCC 21). We use Gaia DR2, Pan-STARRS1 and 2MASS photometry to fit isochrones to the colour-magnitude diagrams of the identified clusters. The ages of the clusters can thus be measured with 10% precision. While four of the clusters have ages between 11 and 13Myr, the ASCC 20 cluster stands out at an age of 21+/-3Myr. This is significantly greater than the age of any previously known component of the Orion complex. To some degree, all clusters overlap in at least one of the six phase-space dimensions. We argue that the formation history of the Orion complex, and its relation to the Gould belt, must be reconsidered. A significant challenge in reconstructing the history of the Ori OB1a association is to understand the impact of the newly discovered 21Myr old population on the younger parts of the complex, including their formation.2019A&A...631A.166Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/631/A166CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/631/A166https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/631/A166http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/631/A166https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/631/A166https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/631/A166http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/631/A166GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/631/A166/table1 (Parameters used in the final step of the clustering algorithm)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/table1?GETtext/xml+votable180.050000true81.1711.3860.005555555555555556Cone search capability for table J/A+A/631/A166/tableb1 (Members of ASCC 16)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/tableb1?GETtext/xml+votable180.050000true81.12571-1.72150.005555555555555556Cone search capability for table J/A+A/631/A166/tableb2 (Members of ASCC 21)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/tableb2?GETtext/xml+votable180.050000true81.178372.58250.005555555555555556Cone search capability for table J/A+A/631/A166/tableb3 (Members of ASCC 21a)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/tableb3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/tableb3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/tableb3?GETtext/xml+votable180.050000true82.58990.117790.005555555555555556Cone search capability for table J/A+A/631/A166/tableb4 (Members of ASCC 20)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/tableb4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/tableb4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/tableb4?GETtext/xml+votable180.050000true81.596370.003740.005555555555555556Cone search capability for table J/A+A/631/A166/tableb5 (Members of ASCC 18)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A166/tableb5?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A166/tableb5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A166/tableb5?GETtext/xml+votable180.050000true81.54291-0.379990.0055555555555555565/5720 5722-5723 5726 5745 5748 6/22839 22845 22886-22887 22897-22899 22908 22910 22977 22996 22998-22999https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/631/A166?format=asciiOpticaldefaultJ/A+A/631/A166/table1Parameters used in the final step of the clustering algorithmSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id;meta.maincharRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainrRadius enclosing 50% of the starsdegphys.angSizefloatpmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloatRVRadial velocitykm/sphys.veloc;pos.heliocentricfloatsigmaVelocity dispersionkm/sphys.veloc.dispersionfloatAgeAgeMyrtime.agefloate_Agerms uncertainty on AgeMyrstat.error;time.agefloatNstarNumber of starsmeta.numberintNstarRVNumber of stars with known radial velocitiesmeta.numberint_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedJ/A+A/631/A166/tableb1Members of ASCC 16recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 id (source_id)meta.idRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainpmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA*rms uncertainty on pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloate_Plxrms uncertainty on Plxmasstat.error;pos.parallaxfloatRV? Radial velocity GALAH and APOGEE surveyskm/sphys.veloc;pos.heliocentricfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexede_RV? rms uncertainty on RVkm/sstat.errorfloatnullableJ/A+A/631/A166/tableb2Members of ASCC 21SimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 id (source_id)meta.idRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainpmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA*rms uncertainty on pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloate_Plxrms uncertainty on Plxmasstat.error;pos.parallaxfloatRV? Radial velocity GALAH and APOGEE surveyskm/sphys.veloc;pos.heliocentricfloatnullablee_RV? rms uncertainty on RVkm/sstat.errorfloatnullableJ/A+A/631/A166/tableb3Members of ASCC 21apmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA*rms uncertainty on pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloate_Plxrms uncertainty on Plxmasstat.error;pos.parallaxfloatRV? Radial velocity GALAH and APOGEE surveyskm/sphys.veloc;pos.heliocentricfloatnullablee_RV? rms uncertainty on RVkm/sstat.errorfloatnullableDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 id (source_id)meta.idRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainJ/A+A/631/A166/tableb4Members of ASCC 20recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 id (source_id)meta.idRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainpmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA*rms uncertainty on pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloate_Plxrms uncertainty on Plxmasstat.error;pos.parallaxfloatRV? Radial velocity GALAH and APOGEE surveyskm/sphys.veloc;pos.heliocentricfloatnullablee_RV? rms uncertainty on RVkm/sstat.errorfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedJ/A+A/631/A166/tableb5Members of ASCC 18recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaGaia DR2 id (source_id)meta.idRA_ICRSRight ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainpmRA*Proper motion along RA, pmnRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA*rms uncertainty on pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPlxAbsolute parallaxmaspos.parallax.trigfloate_Plxrms uncertainty on Plxmasstat.error;pos.parallaxfloatRV? Radial velocity GALAH and APOGEE surveyskm/sphys.veloc;pos.heliocentricfloatnullablee_RV? rms uncertainty on RVkm/sstat.errorfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexed