J/MNRAS/455/2163ivo://CDS.VizieR/J/MNRAS/455/2163doi:10.26093/cds/vizier.74552163CDSOrdonez A.J.Sarajedini A.2024-08-15T20:16:42Z2016-10-06T14:32:36ZCDS support team

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

cds-question@unistra.frgalaxiesvariable-starshst-photometryWe have probed the pulsating variable star content of the isolated Local Group dwarf galaxy, DDO210 (Aquarius), using archival Advanced Camera for Surveys/Hubble Space Telescope imaging in the F475W and F814W passbands. We find a total of 32 RR Lyrae stars (24 ab-type; 8 c-type) and 75 Cepheid variables. The mean periods of the ab-type and c-type RR Lyrae stars are calculated to be <Pab>=0.609+/-0.011 and <Pc>=0.359+/-0.025d, respectively. The light-curve properties of the fundamental mode RR Lyrae stars yield a mean metallicity of <[Fe/H]>=-1.63+/-0.11dex for this ancient population, consistent with a recent synthetic colour-magnitude diagram analysis. We find this galaxy to be Oosterhoff-intermediate and lacking in high-amplitude, short-period ab-type RR Lyrae, consistent with behaviour recently observed for many dwarf spheroidals and ultrafaint dwarfs in the Local Group. We find a distance modulus of {mu}=25.07+/-0.12 as determined by the RR Lyrae stars, slightly larger but agreeing with recent distance estimates from the red giant branch tip. We also find a sizable population of Cepheid variables in this galaxy. We provide evidence in favour of most if not all of these stars being short-period classical Cepheids. Assuming all of these stars to be classical Cepheids, we find that most of these Cepheids are ~ 300 Myr old, with the youngest Cepheids being offset from the older Cepheids and the centre of the galaxy. We conclude that this may have resulted from a migration of star formation in DDO210.2016MNRAS.455.2163Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/455/2163CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/455/2163https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/455/2163http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/455/2163https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/455/2163https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/455/2163http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/455/2163GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/455/2163/table2 (Properties of the pulsating variables in DDO210)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/455/2163/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/455/2163/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/455/2163/table2?GETtext/xml+votable180.050000true311.7024479167-12.85589940.0055555555555555566/48942-48943https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/455/2163?format=asciidefaultJ/MNRAS/455/2163/table2Properties of the pulsating variables in DDO210recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLCShow the light curvesmeta.ref.urlcharVNameStar variable name (VNNNN)meta.id;meta.maincharRAJ2000right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainVTypeVariable typemeta.code;src.varcharPerPerioddtime.periodfloatABAmplitude of variation on B bandmagarith.rate;phot.mag;em.opt.BfloatAIAmplitude of variation on I bandmagarith.rate;phot.mag;em.opt.Ifloat<Bmag>Mean Johnson B magnitude (Vega)magphot.mag;em.opt.Bfloat<Imag>Mean Cousins I magnitude (Vega)magphot.mag;em.opt.Ifloat<B-I>Mean B-I colour indexmagphot.color;em.opt.B;em.opt.IfloatJ/MNRAS/455/2163/table1Time series photometry set for all variable star candidates in DDO210recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVNameStar variable name (VNNNN)meta.id;meta.maincharFilter[F475W F814W] Filtermeta.id;instr.filtercharHJDHeliocentric Julian date (HJD-2456000)dtime.epochdoublemagMagnitude in Filtermagphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloat