J/MNRAS/446/4008ivo://CDS.VizieR/J/MNRAS/446/4008doi:10.26093/cds/vizier.74464008CDSEvans N.R.Szabo R.Derekas A.Szabados L.Cameron C.Matthews J.M.,Sasselov D.Kuschnig R.Rowe J.F.Guenther D.B.Moffat A.F.J.,Rucinski S.M.Weiss W.W.2024-08-14T20:19:18Z2015-11-24T15:55:54ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomybroad-band-photometryThe quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with the Canadian MOST (Microvariability and Oscillations of Stars) satellite. The 3.7-d period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can be modelled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1d period) on the other hand shows light-curve variation from cycle to cycle which we characterize by the variations in the Fourier parameters. We present arguments that we are seeing instability in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O-C curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode pulsator at both long and short time-scales.2015MNRAS.446.4008Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/446/4008CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/446/4008https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/446/4008http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/446/4008https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/446/4008https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/446/4008http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/446/4008GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap3.322582951404819e-19 3.852589004194616e-19OpticaldefaultJ/MNRAS/446/4008/table3O-C values of RT AurigaerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2400000)dtime.epochdoubleEEpoch of the determination in cyclestime.epochintO-CObserved minus computed timedstat.fit.residualfloatWWeigthstat.weightintRefReference for the datameta.ref;pos.frameintJ/MNRAS/446/4008/table5O-C values of SZ TaurirecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2400000)dtime.epochdoubleEEpoch of the determination in cyclestime.epochintO-CObserved minus computed timedstat.fit.residualfloatWWeigthstat.weightintRefReference for the datameta.ref;pos.frameintJ/MNRAS/446/4008/table6New UBV photometric data of SZ TaurecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2400000)dtime.epochdoubleVmagV magnitudemagphot.mag;em.opt.VfloatB-VB-V colour indexmagphot.color;em.opt.B;em.opt.VfloatU-B? U-B colour indexmagphot.color;em.opt.U;em.opt.BfloatnullableJ/MNRAS/446/4008/refsReferencesBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainint