J/A+A/484/463ivo://CDS.VizieR/J/A+A/484/463doi:10.26093/cds/vizier.34840463CDSSterken C.van Genderen A.M.Plummer A.Jones A.F.2017-06-30T05:47:58Z2008-06-30T21:02:34ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomyWide-band photometrymedium-band-photometryWra 751 is a Luminous Blue Variable that lately exhibits strong changes in light and colour. We summarize the available photometry of Wra 751, present new photometric observations, and discuss these data with special attention on the systematic differences between the various data sources. In addition, we establish an empirical relationship between b-y and B-V for this class of stars. Wra 751 is a strong-active member of the S Dor class exhibiting very-long term S Doradus phases with an amplitude of about two magnitudes in V and a cycle length of several decades. The associated B-V colour-index amplitude is about 0.4mag. At this moment this LBV, which is the reddest member of the class, goes through the bright (and red) stage of a long-term S Dor cycle. The S Dor behaviour of this system shows some resemblance to the temporal characteristics of the Galactic LBV AG Car: time scales and amplitudes of light and colour variability are very similar.2008A&A...484..463Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/484/463CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/484/463https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/484/463http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/484/463https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/484/463https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/484/463http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/484/463GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/484/463/table2Walraven photometry (transformed to Johnson V and B-V)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian datedtime.epochdoubleVmagWalraven V magnitude transformed to Johnson Vmagphot.mag;em.opt.VfloatB-VWalraven V-B clour index transformed to Johnson B-Vmagphot.color;em.opt.B;em.opt.VfloatJ/A+A/484/463/table3ASAS differential V photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian datedtime.epochdoubleVmagASAS V magnitudemagphot.mag;em.opt.VfloatJ/A+A/484/463/table4Stromgren y, b-y and transformed B-VrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian datedtime.epochdoubleymagStromgren y magnitude on Johnson V scalemagphot.mag;em.opt.Vfloatb-yStromgren b-y colour indexmagphot.color;em.opt.B;em.opt.VfloatB-V? Johnson B-V colour index derived from b-ymagphot.color;em.opt.B;em.opt.Vfloatnullable