J/AJ/144/92ivo://CDS.VizieR/J/AJ/144/92doi:10.26093/cds/vizier.51440092CDSYang X.H.Fu J.N.Zha Q.2013-11-12T14:51:57Z2013-10-21T06:48:30ZCDS support team

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

cds-question@unistra.frvariable-starsccd-photometryTime-series photometric observations were made for the SX Phoenicis star XX Cyg between 2007 and 2011 at the Xinglong Station of National Astronomical Observatories of China. With the light curves derived from the new observations, we do not detect any secondary maximum in the descending portion of the light curves of XX Cyg, as reported in some previous work. Frequency analysis of the light curves confirms a fundamental frequency f_0_=7.4148cycles/day and up to 19 harmonics, 11 of which are newly detected. However, no secondary mode of pulsation is detected from the light curves. The O-C diagram, produced from 46 newly determined times of maximum light combined with those derived from the literature, reveals a continuous period increase with the rate of (1/P)(dP/dt)=1.19(13)x10^-8^/yr. Theoretical rates of period change due to the stellar evolution were calculated with a modeling code. The result shows that the observed rate of period change is fully consistent with period change caused by evolutionary behavior predicted by standard theoretical models.2012AJ....144...92Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/144/92CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/PASP/125/639 : Time of Maxima for the Sx Phe star BL Cam (Conidis+, 2013)J/MNRAS/419/342 : SX Phe stars in globular clusters (Cohen+, 2012)J/PASP/123/26 : Time of Maxima for the SX Phe star XX Cyg (Conidis+ 2011)J/AJ/139/2639 : DY Peg times of light maximum (Li+, 2010)J/AJ/135/1958 : KZ Hya times of maximum light (Fu+, 2008)J/AZh/84/695 : An SX Phoenicis Variable light curve (Kim+, 2007)J/other/IBVS/5731 : Minima and maxima of 816 variables (Hubscher+, 2006)J/A+A/359/597 : Photometry of SX Phe stars in globular clustersJ/A+AS/100/571 : uvby-beta photometry of SX Phe stars (Rodriguez+ 1993)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/144/92https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/144/92http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/144/92https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/144/92https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/144/92http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/144/92GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/144/92/table4Times of maximum light and O-C values of XX CygrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqRunning sequence numbermeta.id;meta.mainintTmaxObserved times light maxima; HJD-2400000dtime.epochdoubleECycle numbermeta.idintO-CThe O-C valuedstat.fit.residualdoubleRefData source; in refs.dat filemeta.ref;pos.frameintf_Ref[*] * = point not used in O-C because of large discrepancies with the rest of the data)meta.codecharJ/AJ/144/92/refsReferenceComCommentsmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintprimaryBibCodeBibliographic codemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorchar