J/A+AS/116/1ivo://CDS.VizieR/J/A+AS/116/1CDSTomov T.Kolev D.Ivanov M.Antov A.Jones A.Mikolajewski M.,Lepardo A.Passuello R.Saccavino S.Sostero G.Valentinuzzi T.,Bellas-Velidis Y.Dapergolas A.Munari U.1997-12-09T18:04:00Z1997-12-09T19:03:56ZCDS support team

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

cds-question@unistra.frvisible-astronomyWide-band photometryvariable-starsWe present results of an extensive photometric monitoring campaign of the peculiar emission star MWC 560 that covers the range 1990-1995. The time interval corresponds to the length of the proposed orbital period of this highly peculiar binary, which attracted considerable interest in January-April 1990, when absorption components, shifted by -6000km/s from corresponding emission lines, were observed. Here we present photometric data secured during: 113 nights of conventional UBV photoelectric photometry, 45 nights of high speed UBV photoelectric photometry to study the flickering activity, and 682 visual photometric estimates. MWC 560 has experienced a decrease in magnitude since the bright (V=9.2mag) phase in 1990. After the minimum reached in May 1994 (V=10.7mag), the star is currently increasing slowly in brightness. The decrease has been accompanied in all bands by large fluctuations superimposed on the mean trend. The B-V colour has shown a steady increase by 0.0.33mag/yr. U-B has remained stable at -0.07mag since late 1990. In all the observing nights devoted to high speed photometry we observed flickering activity in MWC 560. The data show that the flickering amplitude {DELTA}U increases with the decrease of the U magnitude. Quasi-periodic variations have always been detected. A period of ~70min has been observed in ~13 nights which is close to the ~60min quasi-period reported by Michalitsianos et al. (1993). However, no coherent variability is traceable throughout the whole set of flickering data.1996A&AS..116....1Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/116/1CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+AS/122/43 : V694 Mon plate spectra (Tomov+ 1997)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/116/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/116/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/116/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/116/1https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/116/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/116/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+AS/116/1/table1UBV photoelectric photometryU-B[]? U-B colourmagphot.color;em.opt.U;em.opt.BfloatJDDate of the observationdtime.epochdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVmagStar's magnitude in V bandmagphot.mag;em.opt.Vfloatu_VmagUncertainty flag on Vmagmeta.code.errorcharB-VB-V colourmagphot.color;em.opt.B;em.opt.Vfloatu_B-VUncertainty flag on B-Vmeta.code.errorcharu_U-BUncertainty flag on U-Bmeta.code.errorcharo_VmagNumber of independent measurementsmeta.numberintObsIdentification of the Observatory (1)meta.id;instr.obstycharJ/A+AS/116/1/table2Visual brightness estimates of MWC560 from Nelson (New Zealand)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDDate of the observationdtime.epochdoubleVmagVisual brightness estimatesmagphot.mag;em.opt.Vfloat