J/A+A/488/409ivo://CDS.VizieR/J/A+A/488/409doi:10.26093/cds/vizier.34880409CDSMermilliod J.-C.Queloz D.Mayor M.2018-01-05T08:56:01Z2008-09-27T11:51:41ZCDS support team

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

cds-question@unistra.fropen-star-clustersradial-velocityThe Alpha Persei open cluster (Melotte 20) is one of the nearby clusters (d<500pc) for which a long-term systematic radial-velocity monitoring of the solar-type stars has not been published so far. We undertook an observing program in 1982 to study the membership, duplicity, and rotation of the main-sequence stars and to compare the results with those of the other nearby clusters. Radial-velocity observations of 60 solar-type stars in Mel 20 were obtained with CORAVEL, and of 44 fainter stars with ELODIE spectrographs, in the magnitude range 9.5<V<13.85 The membership of 37 stars from the list compiled by Heckmann is confirmed according to their proper motions, radial velocities, and photometry. We discovered twelve spectroscopic binaries (3 double-lined, 8 single-lined, 1 suspected) among the members and determined an orbit for the double-lined binary He 848. The observed frequency of spectroscopic binaries is therefore 32% (12/37). Four stars are photometric binaries. In addition, the membership of 33 stars with AP numbers is supported by the present radial velocities. Two single-lined and three double-lined binaries were detected in this sample. The cluster mean radial velocity is -1.39+/-0.17km/s based on 18 stars within 2{sigma}. We found a systematic difference of 3.67+/-1.48km/s between observed- and astrometric radial velocities. The Alpha Persei cluster members define a tight main sequence in the colour-magnitude diagrams. The remaining scatter observed in the colour- magnitude diagrams and in radial velocities may be due to the difficulty of separating the core Alpha Persei stars from the extended comoving stream.2008A&A...488..409Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/488/409CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/55 : Radial Velocities in Open Clusters (Mermilliod 1979)III/97 : Radial Velocities in open clusters (Mermilliod 1984)V/80 : Low-Mass Stars Membership in Alpha Persei Cluster (Prosser 1992)J/AN/283/109 : Star positions in the region of alpha Per (Heckmann+, 1956)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/488/409https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/488/409http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/488/409https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/488/409https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/488/409http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/488/409GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/488/409/table3 (ELODIE individual radial velocities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/488/409/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/488/409/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/488/409/table3?GETtext/xml+votable180.050000true49.349708349.35430560.0055555555555555565/442 784 6/1719 1727 1739 1760 1762 1767 1772-1774 3093 3095 3101 3140-3141 3143-3144https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/488/409?format=asciiOpticaldefaultJ/A+A/488/409/table3ELODIE individual radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoStar designation (WEBDA) (1)meta.id;meta.mainintm_No[AB 12] Component (2)meta.code.multipcharHJDHeliocentric Julian datedtime.epochdoubleRVRadial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVError on the radial velocitykm/sstat.errorfloatSimbadNameSimbad column added by the CDSmeta.idchar_RAComputed Right Ascension for Equinox: J2000degpos.eq.ra;meta.main_DEComputed Declination for Equinox: J2000degpos.eq.dec;meta.main