J/MNRAS/463/1332ivo://CDS.VizieR/J/MNRAS/463/1332doi:10.26093/cds/vizier.74631332CDSSoszynski I.Smolec R.Dziembowski W.A.Udalski A.Szymanski M.K.,Wyrzykowski L.Ulaczyk K.Poleski R.Pietrukowicz P.Kozlowski S.,Skowron D.Skowron J.Mroz P.Pawlak M.2024-08-16T20:18:57Z2018-07-03T12:58:58ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsvariable-starsasteroseismologyWe report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars has been extracted from the latest edition of the Optical Gravitational Lensing Experiment collection of RR Lyrae variables in the Magellanic System. The stars pulsating simultaneously in the fundamental (F) and first-overtone (1O) modes have distinctly different properties than regular double-mode RR Lyrae variables (RRd stars). The P_1O_/P_F_ period ratios of our anomalous RRd stars are within a range of 0.725-0.738, while 'classical' double-mode RR Lyrae variables have period ratios in the range of 0.742-0.748. In contrast to the typical RRd stars, in the majority of the anomalous pulsators, the F-mode amplitudes are higher than the 1O-mode amplitudes. The light curves associated with the F-mode in the anomalous RRd stars show different morphology than the light curves of, both, regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode stars show long-term modulations of the amplitudes (Blazhko-like effect). Translating the period ratios into the abundance parameter, Z, we find for our stars Z{in}(0.002, 0.005) - an order of magnitude higher values than typical for RR Lyrae stars. The mass range of the RRd stars inferred from the W_I_ versus P_F_ diagram is (0.55-0.75)M_{sun}_. These parameters cannot be accounted for with single star evolution assuming a Reimers-like mass-loss. Much greater mass-loss caused by interaction with other stars is postulated. We blame the peculiar pulsation properties of our stars to the parametric resonance instability of the 1O-mode to excitation of the F- and 2O-modes as with the inferred parameters of the stars 2{omega}_1O_~={omega}_F_+{omega}_2O_.2016MNRAS.463.1332Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/463/1332CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/463/1332https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/463/1332http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/463/1332https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/463/1332https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/463/1332http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/463/1332GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/463/1332/table1 (Basic properties of anomalous RRd stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/463/1332/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/463/1332/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/463/1332/table1?GETtext/xml+votable180.050000true67.3907964-70.05314280.0055555555555555566/32941 33053-33055 33063 33076 33080 33090-33091 33097-33099 33102 33121 33125 33317 37416 37515https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/463/1332?format=asciidefaultJ/MNRAS/463/1332/table1Basic properties of anomalous RRd starsP1O1O mode perioddtime.perioddoublePFF mode perioddtime.perioddoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharF1O/PFP1O/PF period ratiotime.periodfloatAFFourier amplitude of the fundamental modemagsrc.var.amplitudefloatA1O/AFA1O/AF amplitude ratiosrc.var.amplitude;arith.ratiofloat<Imag>Mean I-band magnitudemagphot.mag;em.opt.Ifloat<Vmag>? Mean V-band magnitudemagphot.mag;em.opt.VfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_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/MNRAS/463/1332/tableaIdentifications of all detected frequencies (tables A1-A22 of the paper)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharFreqIDFrequency identificationmeta.id;phys.atmol.transitionFreqFrequencyd**-1em.freqdoublee_Freq? rms uncertainty on Freqd**-1stat.errordoublenullableA? Amplitudemmagphot.magintnullablee_A? rms uncertainty on Ammagstat.errorintnullablephi? Phaseradtime.phasefloatnullablee_phi? rms uncertainty on radradstat.errorfloatnullableRem[bl ] Remarks (1)meta.notechar