J/MNRAS/517/5704ivo://CDS.VizieR/J/MNRAS/517/5704doi:10.26093/cds/vizier.75175704CDSArmstrong J.J.Wright N.J.Jeffries R.D.Jackson R.J.Cantat-Gaudin T.2024-08-22T20:16:31Z2022-11-14T09:50:55ZCDS support team

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

cds-question@unistra.frstellar-associationsopen-star-clustersspectroscopypre-main-sequence-starsproper-motionsvisible-astronomytrigonometric-parallaxThe kinematics of stars in OB associations can provide insights into their formation, dynamical evolution, and eventual fate. The low-mass stellar content of OB associations are sufficiently numerous as to provide a detailed sampling of their kinematic properties, however spectroscopy is required to confirm the youth of individual stars and to get 3D kinematics. In this paper we present and analyse results from a large spectroscopic survey of Vela OB2 conducted using 2dF/HERMES on the AAT. This spectroscopy is used to confirm the youth of candidate young stars and determine radial velocities, which are combined with proper motions and parallaxes from Gaia to measure 3-dimensional positions and velocities. We identify multiple separate kinematic groups in the region, for which we measure velocity dispersions and infer their virial states. We measure expansion rates for all these groups and find strong evidence for anisotropic expansion in the Vela OB2 association of at least 11 sigma significance in all three dimensions, as well as some evidence for expansion in the gamma Vel and P Puppis clusters. We trace back the motions of these groups into the past and find that the open cluster NGC 2547 is an interloper in the Vela OB2 region and actually formed >100pc away from the association. We conclude that Vela OB2 must have formed with considerable spatial and kinematic substructure over a timescale of ~10Myr, with clear temporal substructure within the association, but no clear evidence for an age gradient.2022MNRAS.517.5704Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/517/5704CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/350 : Gaia EDR3 (Gaia Collaboration, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/517/5704https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/517/5704http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/517/5704https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/517/5704https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/517/5704http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/517/5704GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/517/5704/table1 (Spectroscopic parameters for observed sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/517/5704/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/517/5704/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/517/5704/table1?GETtext/xml+votable180.050000true122.17308362044-45.316386821850.005555555555555556Cone search capability for table J/MNRAS/517/5704/table2 (Astrometric parameters for identified PMS stars with Gaia EDR3 ruwe < 1.4)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/517/5704/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/517/5704/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/517/5704/table2?GETtext/xml+votable180.050000true119.52531590015-48.500665893310.0055555555555555565/9795-9798 9801 9803-9804 9824 6/39175 39179 39196-39197 39201 39203 39211 39220 39222 39224-39226 39234 39300 39302https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/517/5704?format=asciiOpticaldefaultJ/MNRAS/517/5704/table1Spectroscopic parameters for observed sourcesSNR? Signal-to-noise ratiostat.snrfloatnullableRA_ICRSBarycentric right ascension of the source (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainDE_ICRSBarycentric declination of the source (ICRS) at Ep=2016.0degpos.eq.dec;meta.mainEW(Li)? Equivalent-width of Li 6708{AA}0.1pmspect.line.eqWidthdoublenullablee_EW(Li)? Equivalent-width of Li error0.1pmstat.errorfloatnullableHac? H-alpha(core) indexphot.color;em.opt.V;em.line.HalphadoublenullableHaw? H-alpha(wings) indexphot.color;em.opt.V;em.line.HalphafloatnullableEW(Ha)? Equivalent-width of H-alpha 6563A0.1pmspect.line.eqWidthdoublenullableRV? Spectroscopic radial velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_RV? Spectroscopic radial velocity errorkm/sstat.errorfloatnullable_RA.icrsRight ascension (ICRS) at Epoch=J2016. (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2016. (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ/MNRAS/517/5704/table2Astrometric parameters for identified PMS stars with Gaia EDR3 ruwe < 1.4GLONGalactic longitude (l)degpos.galactic.lonGLATGalactic latitude (b)degpos.galactic.latdoubleRVSpectroscopic radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVSpectroscopic radial velocity errorkm/sstat.errorfloatXGalactic Cartesian position in X (1)pcpos.distance;pos.cartesian.x;pos.galacticfloatE_XPositive error of Galactic Cartesian position in X (1)pcstat.error;stat.maxfloate_XNegative error of Galactic Cartesian position in X (1)pcstat.error;pos.cartesian.xfloatYGalactic Cartesian position in Y (1)pcpos.distance;pos.cartesian.y;pos.galacticdoublee_YNegative error of Galactic Cartesian position in Y (1)pcstat.error;pos.cartesian.yfloatZGalactic Cartesian position in Z (1)pcpos.distance;pos.cartesian.z;pos.galacticfloatE_ZPositive error of Galactic Cartesian position in Z (1)pcstat.error;stat.maxfloate_ZNegative error of Galactic Cartesian position in Z (1)pcstat.error;src.redshiftfloatUGalactic Cartesian velocity in X (1)km/sphys.veloc;pos.cartesian.x;pos.galacticfloatE_UPositive error of Galactic Cartesian velocity in X (1)km/sstat.error;stat.maxfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaEDR3Gaia EDR3 source identifier (Cat. I/350)meta.id;meta.mainRA_ICRSBarycentric right ascension of the source (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainRUWERenormalised unit weight errorstat.errorfloat_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_RA_ICRSStandard error e_RA=e_RA*cosDE of the right ascension of the source in ICRS at Ep=2016.0masstat.error;pos.eq.rafloatDE_ICRSBarycentric declination of the source (ICRS) at Ep=2016.0degpos.eq.dec;meta.maine_DE_ICRSStandard error of the declination of the source in ICRS at at Ep=2016.0masstat.error;pos.eq.decfloatPlxAbsolute stellar parallax of the source at the Ep=2016.0maspos.parallaxfloate_PlxStandard error of the stellar parallax at Ep=2016.0masstat.error;pos.parallaxfloatpmRAProper motion in right ascension pmRA*cosDE of the source in ICRS at Ep=2016.0mas/yrpos.pm;pos.eq.rafloate_pmRAStandard error of proper motion in right ascension directionmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in declination directionmas/yrpos.pm;pos.eq.decfloate_pmDEStandard error of proper motion in declination directionmas/yrstat.error;pos.pm;pos.eq.decfloatGmagG-band mean magnitude (Vega)magphot.mag;em.optfloatBPmagIntegrated BP mean magnitude (Vega)magphot.mag;em.opt.BfloatRPmagIntegrated RP mean magnitude (Vega)magphot.mag;em.opt.RfloatE_YPositive error of Galactic Cartesian position in Y (1)pcstat.error;stat.maxfloate_UNegative error of Galactic Cartesian velocity in X (1)km/sstat.error;pos.cartesian.xfloatVGalactic Cartesian velocity in Y (1)km/sphys.veloc;pos.cartesian.y;pos.galacticdoubleE_VPositive error of Galactic Cartesian velocity in Y (1)km/sstat.error;stat.maxfloate_VNegative error of Galactic Cartesian velocity in Y (1)km/sstat.error;pos.cartesian.yfloatWGalactic Cartesian velocity in Z (1)km/sphys.velocfloatE_WPositive error of Galactic Cartesian velocity in Z (1)km/sstat.error;stat.maxfloate_WNegative error of Galactic Cartesian velocity in Z (1)km/sstat.error;pos.cartesian.zfloat