J/A+A/686/A268ivo://CDS.VizieR/J/A+A/686/A268doi:10.26093/cds/vizier.36860268CDSRathour R.S.Hajdu G.Smolec R.Karczmarek P.Hocde V.,Ziolkowska O.Soszynski I.Udalski A.2025-05-23T20:01:11Z2024-09-03T13:29:52ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsvariable-starsmultiple-starsorbitsvisible-astronomyPeriod change studies offer a novel way to probe the evolution and dynamics of Cepheids. While evolutionary period changes have been well studied both observationally and theoretically, non-evolutionary period changes lack a systematic and quantitative description. Here, we deal with one such aspect of non-evolutionary period changes related to a crucial property, namely, the binarity-based nature of a Cepheid. With the advent of long-term photometry surveys covering Magellanic fields, the census of classical Cepheids in binary (or multiple) systems outside the Milky Way is timely. This may have implications for crucial aspects such as the period-luminosity relationship calibrations and our understanding of the nature of Cepheid companions. The overall objective is to have a quantitative understanding of the full picture of non-evolutionary period changes in Cepheids to develop a formalism to disentangle it from the secular evolutionary period change. In the first paper in the series, we aim to conduct a systematic search for non-evolutionary period changes to look for Cepheids in likely binary configurations and quantify their incidence rates in the Magellanic Clouds. We collected more than a decade-long time-series photometry from the publicly available, Optical Gravitational Lensing Experiment (OGLE) survey, with more than 7200 Cepheids altogether from the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC). Our sample contains both fundamental-mode and first-overtone mode Cepheids. Then, we calculate d the observed minus calculated (O-C) diagrams to reveal the light-travel time effect (LTTE). Finally, we calculated the minimum companion masses of the Cepheids and compared them with the predictions from Cepheid population synthesis results. In our search, out of an overall sample of more than 7200 Cepheids, we found 52 candidate Cepheid binary systems in the LMC (30 fundamental and 22 first-overtone mode) and 145 in the SMC (85 fundamental and 60 first-overtone mode). The majority of the sample is characterized by orbital periods of 2000-4000d and eccentricities of 0.2-0.5. Moreover, we report two candidates in each galaxy with the Cepheid likely existing with a giant companion. The incidence rate ratio for SMC to LMC calculated from our sample is in agreement with binary Cepheid population synthesis predictions. In our attempt to quantify the non-evolutionary period change connected with the LTTE, our systematic search has enriched the Cepheid binary sample by a factor of about 2 in both galaxies. The future spectroscopic follow-up can confirm the binarity nature of our sample and constrain the orbital parameters.2024A&A...686A.268Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/686/A268CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/686/A268https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/686/A268http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/686/A268https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/686/A268https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/686/A268http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/686/A268GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/686/A268/tablea1 (List of LMC binary Cepheid candidates with their orbital parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/686/A268/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/686/A268/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/686/A268/tablea1?GETtext/xml+votable180.050000true74.6804094-68.73038310.005555555555555556Cone search capability for table J/A+A/686/A268/tablea2 (List of SMC binary Cepheid candidates with their orbital parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/686/A268/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/686/A268/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/686/A268/tablea2?GETtext/xml+votable180.050000true5.9208739-73.76397720.0055555555555555565/8274 8323 8326 8329 6/33047 33053-33054 33075-33078 33089-33092 33094 33104 33120-33121 33123-33125 33287 33291 33298 33313 33315 33328 33412https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/686/A268?format=asciiOpticaldefaultJ/A+A/686/A268/tablea1List of LMC binary Cepheid candidates with their orbital parametersSimbadSimbad column added by the CDSmeta.ref.urlcharMode[F 1O] Pulsation modemeta.code;src.varcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSampleSample (1)src.samplecharTargetTarget name (NNNN) for OGLE LMC-CEP-NNNN in LMC, OGLE SMC-CEP-NNNN in SMCmeta.id;meta.mainintn_TargetNote (2)meta.notecharFitorderFit orderstat.fit.paramintPpulPulsation perioddtime.perioddoublePorbOrbital perioddtime.periodinte_PorbOrbital period errordstat.errorintT0Time of periastron passagedsrc.orbital.periastroninte_T0Time of periastron passage errordstat.errorinteEccentric anomalysrc.orbital.eccentricityfloate_eEccentric anomaly errorstat.errorfloatasiniasini semi-major axisAUphys.size.smajAxisfloate_asiniasini semi-major axis errorAUstat.errorfloatomegaArgument of periastrondegsrc.orbital.periastroninte_omegaArgument of periastron errordegstat.errorintPCRLinear period-change rated/Myrarith.rate;time.periodfloate_PCRLinear period-change rate errord/Myrstat.errorfloatKSemi-amplitude of the expected radial velocity variation,km/sspect.dopplerVelocfloate_KSemi-amplitude of the expected radial velocity variation errorkm/sstat.errorfloatf(m)Mass functionsolMassphys.massfloate_f(m)Mass function errorsolMassstat.errorfloatMcMass of the companionsolMassphys.massfloatMcepMass of the CepheidsolMassphys.massfloat_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/686/A268/tablea2List of SMC binary Cepheid candidates with their orbital parametersn_TargetNote (2)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchare_omegaArgument of periastron errordegstat.errorintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMode[F 1O] Pulsation modemeta.code;src.varcharSampleSample (1)src.samplecharTargetTarget name (NNNN) for OGLE LMC-CEP-NNNN in LMC, OGLE SMC-CEP-NNNN in SMCmeta.id;meta.mainintFitorderFit orderstat.fit.paramintPpulPulsation perioddtime.perioddoublePorbOrbital perioddtime.periodinte_PorbOrbital period errordstat.errorintT0Time of periastron passagedsrc.orbital.periastroninte_T0Time of periastron passage errordstat.errorinteEccentric anomalysrc.orbital.eccentricityfloate_eEccentric anomaly errorstat.errorfloatasiniasini semi-major axisAUphys.size.smajAxisfloate_asiniasini semi-major axis errorAUstat.errorfloatomegaArgument of periastrondegsrc.orbital.periastronintPCRLinear period-change rated/Myrarith.rate;time.periodfloate_PCRLinear period-change rate errord/Myrstat.errorfloatKSemi-amplitude of the expected radial velocity variation,km/sspect.dopplerVelocfloate_KSemi-amplitude of the expected radial velocity variation errorkm/sstat.errorfloatf(m)Mass functionsolMassphys.massfloate_f(m)Mass function errorsolMassstat.errorfloatMcMass of the companionsolMassphys.massfloatMcepMass of the CepheidsolMassphys.massfloat_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main