J/A+A/713/A293ivo://CDS.VizieR/J/A+A/713/A293CDSMolinaro R.Ripepi V.Marconi M.Gatto M.Trentin E.Deka M.,De Somma G.Musella I.Sicignano T.Ficara F.Leccia S.Luongo E.2026-09-24T07:37:33Z2026-09-24T08:36:45ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomymetallicityEstimating the iron abundance of classical Cepheids (CCs) holds dual significance for stellar population studies. First, understanding the role of metallicity is crucial for defining the period-luminosity (PL) relation, a fundamental step in the cosmic distance scale. Second, as CCs are reliable tracers of young stellar populations, knowledge of their individual metallicities provides a robust estimate of the chemical content of the stellar systems or regions where they are observed. However, estimating their metallicity remains challenging, as it relies primarily on time-consuming spectroscopic observations. The primary objective of this work is to determine if Fourier parameters, extracted from the multi-band photometry provided by the Gaia mission, can serve as proxies for the star's iron abundance ([Fe/H]) to establish a reliable correlation between these pulsational properties and chemical composition. The reference sample comprises 398 CCs from Gaia data release 3, for which high-resolution spectroscopic metallicities are available in the literature, covering the typical pulsation period range of CCs. Focusing exclusively on fundamental mode pulsators, we modelled each light curve with a truncated Fourier series to derive characteristic parameters, such as amplitude ratios and phase differences. A random forest algorithm was applied to this reference set as a feature selection tool to identify the most influential predictors, which were subsequently used to derive an empirical relation for estimating [Fe/H] from photometric properties. We inferred an empirical relation that combines characteristic Fourier parameters extracted from the multi-band Gaia light curves to enable the estimation of the [Fe/H] of fundamental-mode CCs. As a consistency check, we applied this relation to an independent target sample of Cepheids in the Milky Way, the Large Magellanic Cloud, and the Small Magellanic Cloud. The resulting metallicity distributions exhibit three clearly separated peaks, centred near the currently accepted [Fe/H] values of these stellar systems, supporting the predictive capability and external validity of the derived relation.2026A&A...713A.293Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/713/A293CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/713/A293https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/713/A293http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/713/A293https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/713/A293https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/713/A293http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/713/A293GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/713/A293/tablec1 (Spectroscopic and photometric parameters for the calibration fundamental mode Classical Cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/713/A293/tablec1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/713/A293/tablec1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/713/A293/tablec1?GETtext/xml+votable180.050000true71.942978936.72278720.0055555555555555565/8274 9482 6/1239 1426 1858 1985 2684 3020 3045 3070 3182 3196 3342 3616 12968 12971 12987 13032 13201 13288 13931 13933 13990 14047 14205 14238 14260 14262 14337 14340 14388 14402 14404 14409 14431 14436 14600 14607 14609 14618 14625 14718 14770 15360 15424 15618 15633 20805 20818 20827 20849-20850 20852 20862 20945 20958 20980 21511 21514 21542 21632 21648 21664 21671 22046 22055 22068-22069 22073-22074 22122 22124 22207 22218-22219 22223 22267 23619 23640 23660 23662 23727 23755 23763 23778 23852 23936 24002 24088 24138 24149 24340 24424 24450 28717 28808 28875 28916 28918 28991 29089-29090 29095 29102 29104 29106 29160 29166 29216 29468 29510-29511 29897 30128 30210-30211 30258 30313 30452 30659 30688 32067 32955 33001 33054 33076-33078 33095 33103-33104 33106 33108 33112-33113 33120-33122 33124 33294 33298 33304 33306 33317-33318 33328 37203 37223 37235 37240 37247 37329-37330 37332 37334 37336 37340 37357 37361 37364 37674 37706 37713 37721 37723 37729 37734-37735 37737 37739 37745-37747 37791 37821 37828 37856 37859 37867 37888 37895 37897 37903-37906 37917 37923 37927 37932 37936 37938 38016-38017 38020 38023-38024 38026 38029 38048-38049 38403 38408 38627 39189 39191 39196 39225 39228-39230 39232 39239 39244 39271 39277 39283 39293 39314 39317 39321 39326 39348 39364 39381-39382 39392 39405 39410 39416 39419 39697 39704 39737 39748 39750 39754-39755 39759 39766 39771 39773 39782 39790 39793-39794 39796 39799 39831 39838 39871-39872 39875 39880 39883 39886 39889 39892 39896 39898 39903 39905 39908 39913 39920 39930 39933 39935 40491 40494 40608 41375 41385 41461 41595 41599 41605 41626 41631 41651 41661 41667 41673-41674 41681 41721-41722 41759 41762 41765 41768-41769 41780 41810 41813 41833 41862 42155-42156 42171 42185 42378 42445 42453 42500 42820 43012-43013 43022-43023 43028 43040 43056-43057 43060 43722https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/713/A293?format=asciiOpticaldefaultJ/A+A/713/A293/tablec1Spectroscopic and photometric parameters for the calibration fundamental mode Classical Cepheids[Fe/H]Spectroscopic metallicity [Fe/H]phys.abund.Zfloate_[Fe/H]Uncertainty on spectroscopic [Fe/H]stat.error;phys.abund.FefloatR31GFourier amplitude ratio R31 in G bandsrc.var.amplitude;arith.ratiofloate_R31GUncertainty on R31Gstat.errorfloatA1GFourier amplitude A1 in G bandmagsrc.var.amplitudefloate_A1GUncertainty on A1Gmagstat.errorfloatR21RPFourier amplitude ratio R21 in RP bandsrc.var.amplitude;arith.ratiofloate_R21RPUncertainty on R21RPstat.errorfloatA1RPFourier amplitude A1 in RP bandmagsrc.var.amplitudefloate_A1RPUncertainty on A1RPmagstat.errorfloatA2RPFourier amplitude A2 in RP bandmagsrc.var.amplitudefloate_A2RPUncertainty on A2RPmagstat.errorfloatA3RPFourier amplitude A3 in RP bandmagsrc.var.amplitudefloate_A3RPUncertainty on A3RPmagstat.errorfloatrmsGFit rms residuals in G bandmagstat.fit.residual;phot.magfloatrmsBPFit rms residuals in BP bandmagstat.fit.residual;phot.magfloatrmsRPFit rms residuals in RP bandmagstat.fit.residual;phot.magfloatsigBPRaw photometric scatter in BP bandmagstat.stdevfloatsigGRaw photometric scatter in G bandmagstat.stdevfloatsigRPRaw photometric scatter in RP bandmagstat.stdevfloatSimbadSimbad 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.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 Source Identifier (source_id)meta.id;meta.mainPPulsation perioddtime.perioddoublenPtGNumber of points in G band light curvemeta.numberintnPtBPNumber of points in BP band light curvemeta.numberintnPtRPNumber of points in RP band light curvemeta.numberintUIGPhase coverage / Unhedged Index in G bandstat.fit.paramfloatUIBPPhase coverage / Unhedged Index in BP bandstat.fit.paramfloatUIRPPhase coverage / Unhedged Index in RP bandstat.fit.paramfloat