J/AJ/128/2316ivo://CDS.VizieR/J/AJ/128/2316doi:10.26093/cds/vizier.51282316CDSSherry W.H.Walter F.M.Wolk S.J.2005-10-26T21:29:36Z2005-10-26T21:28:19ZCDS support team

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

cds-question@unistra.fropen-star-clusterspre-main-sequence-starsinfrared-photometryvisible-astronomyWide-band photometryWe report an optical photometric survey of 0.89deg^2^ of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest-density region within Orion OB1b. We have developed a statistical procedure to identify the young, low-mass, pre-main-sequence population of the association. We estimate that the cluster has 160 members in the mass range (0.2M_{sun}_<=M<=1.0M_{sun}_). The cluster has a radius of 35pc and an estimated age of 2.5+/-0.3Myr. We estimate that the total mass of the cluster is 225+/-30M_{sun}_. This mass is similar to the estimated mass of the ~5x10^5^yr old cluster NGC 2024. NGC 2024 and sigma Ori appear to be a well-matched pair of clusters, except for the ~2Myr difference in their ages.2004AJ....128.2316Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/128/2316CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/429/1007 : RIJHK photometry of VLM objects near eps Ori (Scholz+, 2005)J/A+A/419/249 : RJHKs photometry of sigma Ori low-mass stars (Scholz+, 2004)J/AN/325/705 : RIJHKs of low-mass stars in sigma Ori (Bejar+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/128/2316https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/128/2316http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/128/2316https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/128/2316https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/128/2316http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/128/2316GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/128/2316/table4 (Photometry of Likely Cluster Members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/128/2316/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/128/2316/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/128/2316/table4?GETtext/xml+votable180.050000true84.920725-2.273397220.0055555555555555566/22851 22854 22857 228608.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/128/2316?format=asciiOpticalInfrareddefaultJ/AJ/128/2316/table3Adopted Color-Temperature Relation for ~3Myr Old StarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpTypeMK spectral type (1)charTeffEffective temperature (2)KintBCBolometric correctionmagfloatU-V? The (U-V) color indexmagfloatnullableB-V? The (B-V) color indexmagfloatnullableV-Rc? The (V-R_C_) color indexmagfloatnullableV-IcThe (V-I_C_) color indexmagfloatV-JThe (V-J) color indexmagfloatV-HThe (V-H) color indexmagfloatV-KThe (V-K) color indexmagfloatV-LThe (V-L) color indexmagfloatJ/AJ/128/2316/table4Photometry of Likely Cluster MembersBmag? The B-band magnitudemagfloatnullablee_Bmag? Error in BmagmagfloatnullableVmagThe V-band magnitudemagfloate_VmagError in VmagmagfloatRcmagThe R_C_ band magnitudemagfloate_RcmagError in RmagmagfloatIcmagThe I_C_ band magnitudemagfloate_IcmagError in ImagmagfloatJmag? 2MASS J-band magnitude (2)magfloatnullablee_Jmag? Error in JmagmagfloatnullableHmag? 2MASS H-band magnitude (2)magfloatnullablee_Hmag? Error in HmagmagfloatnullableKsmag? 2MASS Ks-band magnitude (2)magfloatnullablee_Ksmag? Error in KsmagmagfloatnullableMassEstimated mass (3)solMassfloatProbMembership probability%intrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Hour of right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000) (1) (1)pos.eq.dec;meta.main