J/MNRAS/477/3197ivo://CDS.VizieR/J/MNRAS/477/3197doi:10.26093/cds/vizier.74773197CDSReino S.De Bruijne J.Zari E.D'Antona F.Ventura P.2024-08-18T20:19:12Z2021-08-20T13:13:16ZCDS support team

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

cds-question@unistra.fropen-star-clustersradial-velocityWe present a study of the membership of the Hyades open cluster, derive kinematically modelled parallaxes of its members, and study the colour-absolute magnitude diagram of the cluster. We use Gaia DR1 Tycho-Gaia Astrometric Solution (TGAS) data complemented by Hipparcos-2 data for bright stars not contained in TGAS. We supplement the astrometric data with radial velocities collected from a dozen literature sources. By assuming that all cluster members move with the mean cluster velocity to within the velocity dispersion, we use the observed and the expected motions of the stars to determine individual cluster membership probabilities. We subsequently derive improved parallaxes through maximum-likelihood kinematic modelling of the cluster. This method has an iterative component to deal with 'outliers', caused for instance by double stars or escaping members. Our method extends an existing method and supports the mixed presence of stars with and without radial velocities. We find 251 candidate members, 200 of which have a literature radial velocity, and 70 of which are new candidate members with TGAS astrometry. The cluster is roughly spherical in its centre but significantly flattened at larger radii. The observed colour-absolute magnitude diagram shows a clear binary sequence. The kinematically modelled parallaxes that we derive are a factor ~1.7/2.9 more precise than the TGAS/ Hipparcos-2 values and allow us to derive an extremely sharp main sequence. This sequence shows evidence for fine-detailed structure that is elegantly explained by the full spectrum turbulence model of convection.2018MNRAS.477.3197Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/477/3197CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/477/3197https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/477/3197http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/477/3197https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/477/3197https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/477/3197http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/477/3197GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/477/3197/table (Radial velocities of Hyades members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/3197/table?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/3197/table?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/3197/table?GETtext/xml+votable180.050000true58.170874425.80443690.0055555555555555565/84 87 5881 5883-5884 5886 6/60 75 78 151 165 186 272-273 309 311 320 322-323 325 333-334 340-342 353 357 373 375 383 421-422 456 472 477-478 483 507 540 567 586 601 770 812 816 835 840 882 890 917 1024-1026 1032-1033 1035 1042 1045 1052 1058 1060 1064 1075 1077 1091 1129 1167 1211 1232 17756 17904 22855 22907 22928 23017-23018 23023 23026 23216 23286 23299 23313 23321 23329 23332 23339 23344 23383 23388 23392 23396 23405 23410 23416 23423 23450 23454 23463 23478-23479 23489-23493 23496-23497 23499 23501-23504 23511 23513-23515 23518-23519 23522-23523 23529 23542 23548 23550 23561 23603 23695 23714 23733 24068 24075 24099 24104 24110 24130 24137 24156 24173 24177 24185 24192 24194-24195 24201-24203 24206-24209 24211-24212 24218 24223 24232 24234 24242 24248 24251-24252 24258 24315 24476https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/477/3197?format=asciidefaultJ/MNRAS/477/3197/tableRadial velocities of Hyades membersSimbadNameSimbad column added by the CDSmeta.idcharHIP? Hipparcos identifiermeta.idintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTYCTycho-2 identifiermeta.id;meta.maincharGaiaDR1? Gaia DR1 identifier (source_id)meta.idnullablecc-value (chi-squared) of the starstat.fit.chi2doublepp-value of the star corresponding to the c-valuestat.fit.goodnessfloatRV? Radial velocity (in km/s)km/sphys.veloc;pos.heliocentricfloatnullablee_RV? Radial velocity error (which have been inflated due to the zero-point differences)km/sstat.errorfloatnullabler_RV? Source of the radial velocity measurement (1)meta.ref;pos.frameintnullableplxmod? Kinematically modelled parallax for this star (if missing then the star was rejected during kinematic modelling)maspos.parallax;meta.modelledfloatnullablee_plxmod? Standard deviation of the modelled parallaxmasstat.errorfloatnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main