J/A+A/703/A155ivo://CDS.VizieR/J/A+A/703/A155CDSPlachy E.Netzel H.Bodi A.2026-03-02T06:25:50Z2025-11-17T09:08:26ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyvariable-starsphotometryvisible-astronomyClassical Cepheid stars that pulsate in the first overtone radial mode often exhibit additional periodicities at the millimagnitude level. Extensive studies of the OGLE data of the Magellanic Clouds have revealed distinct groups based on the ratio of the star's additional period to the period of the first overtone mode. These groups are similar to those found in overtone RR Lyrae stars. Theoretical calculations suggest that some of the observed periodicities are consistent with non-radial modes, while others remain unexplained. Currently, we only know of a handful of examples from the Galactic Cepheid sample that exhibit low-amplitude periodicities. The purpose of this study is to undertake a systematic search for low-amplitude variability in overtone Cepheids of the Milky Way in the photometric data of the full-frame images of the Transiting Exoplanet Survey Satellite (TESS), which were produced with the MIT Quick Look Pipeline. We applied standard Fourier analysis and classified the additional signals according to the ratio of their period to the overtone pulsation period. We find 127 stars in total that exhibit additional periodicities. In 17 of these stars, the periodicities can be identified as a second radial overtone. A further 83 of the stars were observed to display periodic signals with a Px/P1O ratio in the range 0.60-0.65. In 15 stars, the P1O/Px is found to be ~0.68; six of these stars are also found to be in the previous group. Furthermore, we observed the presence of low-amplitude signals in 22 stars outside the aforementioned period ratio ranges. It is possible that some are direct detections of non-radial modes, with no harmonic frequency peak in the 0.60-0.65 period range. Most of the properties of the additional signals detected in this study are consistent with previous findings regarding Cepheids in the Magellanic Clouds. However, TESS measurements reveal that the amplitudes and frequencies of these signals often vary within a TESS sector, a phenomenon that challenges theoretical models. We also find that reliable analysis of these signals with TESS is possible for a moderate fraction of overtone Cepheids. The primary constraints are the limited extent of the data and the relatively poor photometric quality in some Galactic fields. Further careful corrections to the light curves may improve detectability.2025A&A...703A.155Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/703/A155CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)J/MNRAS/478/1425 : Single-mode OGLE Cepheids additional modes (Suveges+, 2018)J/AcA/69/305 : Northern Galactic disk classical Cepheids (Skowron+, 2019)J/AcA/70/101 : OGLE IV Galactic Cepheids (Soszynski+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/703/A155https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/703/A155http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/703/A155https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/703/A155https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/703/A155http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/703/A155GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/703/A155/table2 (Name list of stars with additional periodicities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A155/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A155/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A155/table2?GETtext/xml+votable180.050000true109.473505-19.844523060.0055555555555555566/1653 1799-1800 1803 1806 1861 1924 2943 3022 3052 3063 3187 3196 3270 3278 3332 3336 3601 3632 3682 3718 3721 3726 13026 14212 14271 14329 14600 14677-14678 14709 14730 15363 15414 15438 15448 15453-15454 15464 15478 15504 15638 15660 15959 20819 20821 20854 20861 20945 20953 20957 20978 21509 21513 21544 21634 21638 21672 21677 22021 22047 22064 22106 22112 22172 22181 22191 22220 22223 22432 23623 23650 23659 23663 23756 23769 23808 23846 23942 23967 24145-24146 24226 24327 24339 24377 24455 24462 24481 24512 24552 28839 30620 30652 37205 37315 37342 37712 37720 37734 37895 38436 39217 39248 39369 39417 39743 39779 39784 39873 39878 39894 39908 39919 40634 41556 41675 41733 41794 41823 43020-43021 43044 43064https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/703/A155?format=asciiOpticaldefaultJ/A+A/703/A155/table2Name list of stars with additional periodicitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintmoreindicates data in other tablesmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharTICTESS identification of the starmeta.id;meta.mainlongprimaryGaiaDR3Gaia identification of the starmeta.idOtherOther identification of the starmeta.idcharRAJ2000Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainTmagBrightness in TESS passbandmagphot.mag;em.optfloatGroupGroup of the additional mode (1)meta.idcharJ/A+A/703/A155/table3New 1O2O stars found in the analyzed samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Identification of the starmeta.id;meta.mainlongSectorsSectors in which the star was observedobs.fieldcharf1OFrequency of the first overtonec.d**-1em.freq;src.vardoublee_f1OFrequency of the first overtone errorc.d**-1stat.errordoubleA1OFourier amplitude of the first overtone, in relative flux ubitssrc.var.amplitudefloate_A1OFourier amplitude of the first overtone error, in relative flux ubitsstat.errorfloatf2OFrequency of the second overtonec.d**-1em.freq;src.vardoublee_f2OFrequency of the second overtone errorc.d**-1stat.errordoubleA2OFourier amplitude of the second overtone, in relative flux ubitssrc.var.amplitudedoublee_A2OFourier amplitude of the second overtone error, in relative flux ubitsstat.errordoublef1O/f2OFrequency ratioem.freq;arith.ratiodoublee_f1O/f2OFrequency ratio errorstat.errordoubleA2O/A1OAmplitude ratiosrc.var.amplitude;arith.ratiofloate_A2O/A1OAmplitude ratio errorstat.errorfloatJ/A+A/703/A155/table4Stars with additional frequencies near the P_1O_/P0_68_~0.68 ratiorecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Identification of the starmeta.id;meta.mainlongSectorsSectors in which the star was observedobs.fieldcharf1OFrequency of the first overtonec.d**-1em.freq;src.vardoublee_f1OFrequency of the first overtone errorc.d**-1stat.errordoubleA1OFourier amplitude of the first overtone, in relative flux unitssrc.var.amplitudedoublee_A1OFourier amplitude of the first overtone error, in relative flux unitsstat.errordoublef0.68Frequency at P1O/P0.68~0.68c.d**-1em.freq;src.vardoublee_f0.68Frequency at P1O/P0.68~0.68 errorc.d**-1stat.errordoublef0.68/f1OFrequency ratioem.freq;arith.ratiofloate_f0.68/f1OFrequency ratio errorstat.errorfloatA0.68/A1OAmplitude ratiosrc.var.amplitude;arith.ratiofloate_A0.68/A1OAmplitude ratio errorstat.errorfloatRemarksRemarks (G1)meta.notecharJ/A+A/703/A155/table5Stars with additional frequencies near the P_0.61_/P_1O_~0.60-0.65 ratioe_A1O? Fourier amplitude of the first overtone error, in relative flux unitsstat.errordoublenullablef0.61? Frequency in P_0.61/_P_1O_~0.60-0.65 rangec.d**-1em.freq;src.vardoublenullablefsh? Subharmonic frequency at 0.5f_0.61_c.d**-1em.freq;src.vardoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Identification of the starmeta.id;meta.mainlongSectorsSectors in which the star was observedobs.fieldcharf1O? Frequency of the first overtonec.d**-1em.freq;src.vardoublenullablee_f1O? Frequency of the first overtone errorc.d**-1stat.errordoublenullableA1O? Fourier amplitude of the first overtone, in relative flux unitssrc.var.amplitudedoublenullablee_f0.61? Frequency in P_0.61/_P_1O_~0.60-0.65 range errorc.d**-1stat.errordoublenullablee_fsh? Subharmonic frequency at 0.5f_0.61_ errorc.d**-1stat.errordoublenullablef0.61/f1O? Frequency ratioem.freq;arith.ratiodoublenullablee_f0.61/f1O? Frequency ratio errorstat.errordoublenullableA0.61/A1O? Amplitude ratio with the first overtonesrc.var.amplitude;arith.ratiofloatnullablee_A0.61/A1O? Amplitude ratio with the first overtonestat.errorfloatnullableAsh/A0.61? Amplitude ratio with the subharmonicsrc.var.amplitude;arith.ratiofloatnullablee_Ash/A0.61? Amplitude ratio with the subharmonicstat.errorfloatnullableRemarksRemarks (G1)meta.notecharJ/A+A/703/A155/table6Stars with other additional frequenciesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Identification of the starmeta.id;meta.mainlongSectorsSectors in which the star was observedobs.fieldcharf1O? Frequency of the first overtonec.d**-1em.freq;src.vardoublenullablee_f1O? Frequency of the first overtone errorc.d**-1stat.errordoublenullableA1O? Fourier amplitude of the first overtone, in relative flux unitssrc.var.amplitudedoublenullablee_A1O? Fourier amplitude of the first overtone error, in relative flux unitsstat.errordoublenullablefxAdditional frequencyc.d**-1em.freq;src.vardoublee_fxAdditional frequencyc.d**-1stat.errordoubleAxFourier amplitude of the additional signal, in relative flux unitssrc.var.amplitudedoublee_AxFourier amplitude of the additional signal error, in relative flux unitsstat.errordoublefx/f1OFrequency ratioem.freq;arith.ratiofloate_fx/f1OFrequency ratio errorstat.errorfloatAx/A1OAmplitude ratiosrc.var.amplitude;arith.ratiofloate_Ax/A1OAmplitude ratio errorstat.errorfloatRemarksRemarks (G1)meta.notechar