J/AJ/113/2104ivo://CDS.VizieR/J/AJ/113/2104doi:10.26093/cds/vizier.51132104CDSTurner D.G.Mandushev G.I.Welch G.A.2023-04-06T16:50:24Z1998-08-31T13:53:31ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomybroad-band-photometryradial-velocityPhotoelectric, CCD, and photographic photometry is presented for a sample of 163 stars in the field of the short-period Cepheid SU Cyg for the purpose of searching for a putative cluster that might be associated with the Cepheid. Although the variable is situated in a clump of stars that has the appearance of a sparse cluster, the photometric evidence indicates that they are not a physical group. About two dozen B and A-type stars randomly distributed in the field lie at a common distance of 1086+/-60pc (V_0_-M_V_= 10.18+/-0.12 for R=2.94+/-0.38), but they are likely to represent at best a segment of the Vul OB4 association, which overlaps the region. SU Cyg is unlikely to be a member of that group. The close optical companion to SU Cyg, an A2 V star with a radial velocity (<VR>=-23.6+/-7.1km/s) close to the systemic velocity of the Cepheid, is a spectroscopic binary that might be physically related to the variable. Its primary importance is for helping to establish a space reddening of E_(B-V_)=0.15+/-0.01 for SU Cyg. Despite the lack of related cluster stars to SU Cyg, its two unresolved companions can be used to place restrictions on the likely luminosity of the Cepheid. The resulting value of <M_V_><=-3.02+/-0.23 relative to its companions agrees closely with a value of <MV>(PLC)=-3.03+/-0.07 obtained from the Cepheid PLC relation.1997AJ....113.2104Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/113/2104CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/113/2104https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/113/2104http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/113/2104https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/113/2104https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/113/2104http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/113/2104GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/113/2104/table1Photoelectric UBV data for stars in the field of SU CygrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharHDE? HDE numbermeta.idintnullableVmagV magnitudemagphot.mag;em.opt.VfloatB-VB-V colour indexmagphot.color;em.opt.B;em.opt.VfloatU-Bcolour indexmagphot.color;em.opt.U;em.opt.Bfloatn_Vmag? Number of nights of observations for stars 1 to 10meta.noteintnullableNUBV? Number of published UBV observations for FM starsmeta.numberintnullableNtsc? Number of transformed system colors for FM starsmeta.numberintnullableSpTypeAvailable spectral type (MK/HDE)src.spTypecharJ/AJ/113/2104/table2CCD BV photometry for faint stars near SU Cyg.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar numbermeta.id;meta.mainintn_Star[cd] Note on star (1)meta.notecharVmag? V magnitudemagphot.mag;em.opt.Vfloatnullableu_VmagUncertainty flag on Vmagmeta.code.errorcharn_Vmag[ab] Note on Vmag (2)meta.notecharB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullableu_B-VUncertainty flag on B-Vmeta.code.errorcharn_B-V[ab] Note on B-V (2)meta.notecharU-B? U-B colour indexmagphot.color;em.opt.U;em.opt.Bfloatnullableu_U-BUncertainty flag on U-Bmeta.code.errorcharJ/AJ/113/2104/table3Photographic UBV photometry for stars near SU CygrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar numbermeta.id;meta.mainintn_Star[cd] Note on star (1)meta.notecharVmag? V magnitudemagphot.mag;em.opt.Vfloatnullableu_VmagUncertainty flag on Vmagmeta.code.errorcharn_Vmag[ab] Note on Vmag (2)meta.notecharB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullableu_B-VUncertainty flag on B-Vmeta.code.errorcharn_B-V[ab] Note on B-V (2)meta.notecharU-B? U-B colour indexmagphot.color;em.opt.U;em.opt.Bfloatnullableu_U-BUncertainty flag on U-Bmeta.code.errorchar