J/A+A/700/A201ivo://CDS.VizieR/J/A+A/700/A201doi:10.26093/cds/vizier/bc-nw/lcabCDSMonelli M.Piersimoni A.-M.Martinez-Vazquez C.-E.Cassisi S.,Stetson P.-B.Marconi M.Perez-Garcia P.-J.Bono G.Dall'Ora M.,Fiorentino G.Gallart C.Marengo M.2026-08-03T06:56:25Z2025-08-21T08:39:12ZCDS support team

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

cds-question@unistra.frgalaxiesvariable-starsinfrared-photometryvisible-astronomybroad-band-photometrystellar-distancePulsating variable stars are invaluable tracers for reconstructing the star formation history and chemical evolution of their host galaxies. In this work, we explore the variable star population of Leo II, a distant dwarf spheroidal satellite of the Milky Way. We analyse an extensive dataset of ground-based BVRI time-series photometry spanning over 35 years. By examining the properties of RR Lyrae stars, we constrain the early chemical enrichment and spatial variation within Leo II. Additionally, we investigate the anomalous Cepheids in order to connect their characteristics with the galaxy's prolonged star formation history, as revealed by deep HST/WFC3 colour-magnitude diagrams. We identified and characterised 175 variable stars, with all but one associated with Leo~II. Our work includes the discovery of 25 new RR Lyrae stars and two new anomalous Cepheids. Moreover, we reclassified V88 as a BL Her variable star. By employing multiple independent methods, including metallicity-luminosity relations for RR Lyrae stars and period-luminosity and period-Wesenheit relations for both RR Lyrae and anomalous Cepheids, we derived a true distance modulus of (m-M)_0=21.60+/-0.03mag, corresponding to 209+/-4kpc. Furthermore, we discuss potential formation scenarios for anomalous Cepheids and suggest that, despite the extended star formation history, they are all compatible having originated from old binary stars, with no contribution from young, evolved single stars.2025A&A...700A.201Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/700/A201CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/120/284 : Variables in Leo II dwarf spheroidal (Siegel+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/700/A201https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/700/A201http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/700/A201https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/700/A201https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/700/A201http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/700/A201GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/700/A201/table2 (Summary table of detected variable stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/700/A201/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/700/A201/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/700/A201/table2?GETtext/xml+votable180.050000true168.347166722.21583330.0055555555555555566/283612.762881831355591e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/700/A201?format=asciiOpticalInfrareddefaultJ/A+A/700/A201/table2Summary table of detected variable starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLCShow the light curvesmeta.ref.urlcharStarVariable star identifier (V1 to V201), [SM2000] VNNN in Simbadmeta.id;meta.maincharRAJ2000Right Ascension J2000, Epoch 2000.0pos.eq.ra;meta.mainDEJ2000Declination J2000, Epoch 2000.0pos.eq.dec;meta.mainPerPerioddtime.perioddouble<Bmag>Mean B magnitudemagphot.mag;em.opt.BfloatABAmplitude in B bandmagphot.magfloat<Vmag>Mean V magnitudemagphot.mag;em.opt.VfloatAVAmplitude in V bandmagphot.magfloat<Rmag>? Mean R magnitudemagphot.mag;em.opt.RfloatnullableAR? Amplitude in R bandmagsrc.var.amplitudefloatnullable<Imag>Mean I magnitudemagphot.mag;em.opt.RfloatAIAmplitude in I bandmagsrc.var.amplitudefloat[Fe/H]? Photometric metallicity derived from the Period-Metallicity-Luminosity relation in the I bandmeta.notefloatnullableTypetype of variable starsrc.classcharModePulsation modemeta.code;src.varcharQ1[0/1] Quality flag for light curve (1)meta.code.qualintSimbadNameSimbad column added by the CDSmeta.idcharnullableJ/A+A/700/A201/table3Time series photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarVariable star identifier (V1 to V201)meta.id;meta.maincharFilter[BVRI] Filterinstr.bandpasscharHJDModified Heliocentric Julian date of mid-exposure (HJD-2400000)dtime.epochdoubleindexedmagMagnitude in Filtermagphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloat