J/ApJS/194/27ivo://CDS.VizieR/J/ApJS/194/27doi:10.26093/cds/vizier.21940027CDSHenderson C.B.Stanek K.Z.Pejcha O.Prieto J.L.2017-11-06T12:24:13Z2011-10-05T10:18:20ZCDS support team

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

cds-question@unistra.frvariable-starsinfrared-photometryvisible-astronomyphotometrystellar-associationssurveysWe present a catalog of photometrically variable stars discovered within two 21.3'x21.3' fields centered on the Cygnus OB2 association (Cyg OB2). There have hitherto been no deep optical variability studies of Cyg OB2, despite it being replete with early-type massive stars, likely due to the high and variable extinction (up to A_V_~20) that permeates much of the region. Here, we provide results of the first variability study with this combination of spatial coverage (~0.5deg) and photometric depth (R~21mag). We find 121 stars to be variable in both R and I bands, 115 of them newly discovered. Of the 121 variables, we identify 27 eclipsing binaries and eclipsing-binary candidates, 52 pulsating variables, and 20 potential Herbig Ae/Be stars. Confirming both the status and the cluster membership of the Herbig Ae/Be stars would address the uncertainty regarding the age and star formation history of Cyg OB2. We match our catalog to known variables and binaries in the region, Two Micron All Sky Survey near-IR data, and Chandra X-ray observations to find counterparts to new variables in other wavelengths.2011ApJS..194...27Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/194/27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/ApJS/184/84 : X-ray sources in Cyg OB2 region (Wright+, 2009)J/A+A/486/453 : NIR photometry of early-type stars in Cyg OB2 (Comeron+,J/A+A/464/211 : Chandra and near-IR obs. of Cyg OB2 (Albacete Colombo+, 2007)J/A+A/472/557 : Cygnus OB2 region 610MHz sources (Marti+, 2007)J/ApJ/643/238 : Chandra/2MASS sources in Cygnus OB2 (Butt+, 2006)J/ApJS/149/123 : WSRT survey of Cygnus OB2 (Setia Gunawan+, 2003)J/MNRAS/298/753 : Variables in Cygnus OB2 (Pigulski+ 1998)J/AJ/107/1433 : Cygnus OB2 polarimetry (Kobulnicky+, 1994)http://www.astronomy.ohio-state.edu/~henderson/cygnusvariability/ : lighthttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/194/27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/194/27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/194/27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/194/27https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/194/27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/194/27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/194/27/table2 (Parameters of the 121 variable stars identified in this study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/194/27/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/194/27/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/194/27/table2?GETtext/xml+votable180.050000true307.7507541.57501940.0055555555555555566/14692 14693 146948.650015785639275e-20 3.3785437584409506e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/194/27?format=asciiOpticalInfrareddefaultJ/ApJS/194/27/table2Parameters of the 121 variable stars identified in this studyTypeVariable type (3)meta.code;src.varcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDVariable identification (<[HSP2011] NNN> in Simbad)meta.id;meta.mainintu_Per[~] Uncertainty flag on Permeta.code.errorcharPer? Perioddtime.perioddoublenullablef_Per[i] i: Irregular periodmeta.codecharRampR-band peak-to-peak amplitudemagsrc.var.amplitude;em.opt.Rfloat2MASS2MASS identification (HHMMSSss+DDMMSSs)meta.id.crosscharRcmagMean Cousins R-band magnitudemagphot.mag;em.opt.RfloatIcmagMean Cousins I-band magnitudemagphot.mag;em.opt.IfloatJmag? 2MASS J-band magnitudemagphot.mag;em.IR.JfloatnullableHmag? 2MASS H-band magnitudemagphot.mag;em.IR.HfloatnullableKsmag? 2MASS Ks-band magnitudemagphot.mag;em.IR.KfloatnullableX[YNO] Chandra X-ray match (1)meta.codecharXv[CVP] X-ray variability (2)meta.codecharSimbadSimbad column added by the CDSmeta.refcharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.main