J/A+AS/118/503ivo://CDS.VizieR/J/A+AS/118/503CDSTian K.P.van Leeuwen F.Zhao J.L.Su C.G.2002-06-06T16:15:57Z2002-06-06T16:15:48ZCDS support team

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

cds-question@unistra.fropen-star-clustersproper-motionsRelative proper motions and membership probabilities for 333 stars within an area of 1.6deg by 1.8deg centred on the Orion Nebula M 42 are determined using plates taken over a period of 83 years with the double astrograph of Shanghai Observatory (scale of 30"/mm). The plates were measured with the ASTROSCAN automatic plate-measuring machine of Leiden Observatory. The average proper motion accuracy obtained for stars in the photographic magnitude range 7 to 14 is 0.3mas/yr. Errors are somewhat larger towards fainter and brighter magnitude, but the majority lie well below 1mas/yr. 64% of the stars have been measured successfully on at least 13 out of 18 plates. The number of stars with membership probabilities higher than 0.7 is 184. It is shown by a detailed discussion that the proper motions and membership probabilities of the stars determined in this paper are in good agreement with the results presented recently by other authors. Although there is a clear concentration in the proper motion diagram, both the remaining dispersion of the internal motions and the distribution of "members" as projected on the sky indicate that the stars in this region are not bound as one system, but do have a common origin. A similar conclusion can be drawn from a comparison with spectroscopic and radial velocity data.1996A&AS..118..503Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/118/503CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/171 : PARENAGO Catalogue of stars in the area of the Orion Nebulahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/118/503https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/118/503http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/118/503https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/118/503https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/118/503http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/118/503GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+AS/118/503/table3 (Results of the astrometric study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+AS/118/503/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+AS/118/503/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+AS/118/503/table3?GETtext/xml+votable180.050000true83.10694583-4.796288890.0055555555555555565/5359 6/21482 22804-22805 22807 22848https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+AS/118/503?format=asciiOpticaldefaultJ/A+AS/118/503/table3Results of the astrometric studyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNo[1/406]+ Sequential numbermeta.id;meta.mainintprimaryindexedParenagoParenago number (Catalogue <II/171>)meta.idintPmagPhotographic magnitudemagphot.mag;em.optfloatRAJ2000Right ascension (J2000, Epoch 1950)pos.eq.ra;meta.maine_RAsrms uncertainty on RAmsstat.errorintDEJ2000Declination (J2000, Epoch 1950)pos.eq.dec;meta.maine_DEsrms uncertainty on DEmasstat.errorintpmRAProper motion along RAmas/yrpos.pm;pos.eq.rafloate_pmRArms uncertainty on proper motion RAmas/yrstat.errorfloatpmDEProper motion in DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on proper motion DEmas/yrstat.errorfloatPlateNumber of plates usedmeta.numberintEp-1950Mean epoch in years, relative to 1950.0yrtime.epochfloatMembMembership probability in percents%stat.fit.goodnessint