J/A+A/436/853ivo://CDS.VizieR/J/A+A/436/853doi:10.26093/cds/vizier.34360853CDSLodieu N.McCaughrean M.J.Barrado y Navascues D.Bouvier J.,Stauffer J.R.2018-03-08T14:47:38Z2005-07-24T21:56:23ZCDS support team

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

cds-question@unistra.fropen-star-clustersccd-photometryinfrared-photometryWe present a near-infrared (K'-band) survey of 0.7 square degree area in the {alpha} Persei open cluster (age=90Myr, distance=182pc) carried out with the Omega-Prime camera on the Calar Alto 3.5-m telescope. Combining optical data (Rc and Ic) obtained with the KPNO/MOSA detector and presented in Stauffer et al. (1999ApJ...527..219S; S99) with the K' observations, a sample of new candidate members has been extracted from the optical-infrared colour-magnitude diagram. The location of these candidates in the colour-colour diagram suggests that two-thirds of them are actually reddened background giants. About 20 new candidate members with masses between 0.3 and 0.04M_{sun}_ are added to the ~400 known Alpha Per cluster members. If they are indeed Alpha Per members, four of the new candidates would be brown dwarfs. We discuss the advantages and drawbacks of the near-infrared survey as compared to the optical selection method. We also describe the outcome of optical spectroscopy obtained with the Twin spectrograph on the Calar Alto 3.5-m telescope for about 30 candidates, including selected members from the optical sample presented in Barrado y Navascues et al. (2002, Cat. <J/A+A/395/813>) and from our joint optical/infrared catalogue. These results argue in favour of the optical selection method for this particular cluster.2005A&A...436..853Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/436/853CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/395/813 : Alpha Per faint stars photometry (Barrado y Navascues+, 2002)J/A+A/416/125 : RI photometry in alpha Per and Pleiades (Deacon+, 2004)J/AN/319/201 : Alpha Per cluster low-mass members. I. (Prosser+, 1998)J/AN/319/215 : Alpha Per cluster low-mass members. II. (Prosser+, 1998)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/436/853https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/436/853http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/436/853https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/436/853https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/436/853http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/436/853GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/436/853/table2 (Matched objects between the optical (Stauffer et al. (1999ApJ...527..219S, S99) and the near-infrared catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/436/853/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/436/853/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/436/853/table2?GETtext/xml+votable180.050000true52.117208349.60152780.0055555555555555565/784 6/3093 3095 31012.367228618189496e-19 3.3785437584409506e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/436/853?format=asciiInfrareddefaultJ/A+A/436/853/table2Matched objects between the optical (Stauffer et al. (1999ApJ...527..219S, S99) and the near-infrared catalogueSeqIdentification numbermeta.id;meta.mainintAPnameObject name (1)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Optical Right ascension (J2000.0)pos.eq.ra;meta.mainindexedDEJ2000Optical Declination (J2000.0)pos.eq.dec;meta.mainRAINear-infrared Right ascension (J2000.0)pos.eq.raDEINear-infrared Declination (J2000.0)pos.eq.raK'magK' magnitudemagphot.mag;em.IR.Kfloate_K'magError on the K' magnitudemagstat.error;phot.mag;em.IR.KfloatRcmagR_c magnitude from KPNO/MOSA (S99)magphot.mag;em.opt.Rfloate_RcmagError on the R_c magnitude (S99)magstat.error;phot.mag;em.opt.RfloatIcmagI_c magnitude from KPNO/MOSA (S99)magphot.mag;em.opt.Ifloate_IcmagError on the I_c magnitude (S99)magstat.error;phot.mag;em.opt.IfloatSimbadSimbad column added by the CDSmeta.ref.urlchar