J/A+A/678/A195ivo://CDS.VizieR/J/A+A/678/A195doi:10.26093/cds/vizier/bc-n6/lbjfCDSda Silva R.D'Orazi V.Palla MBono G.Braga V.F.Fabrizio M.,Lemasle B.Spitoni E.Matteucci F.Joensson H.Kovtyukh V.Magrini L.,Bergemann M.Dall'Ora M.Ferraro I.Fiorentino G.Francois P.,Iannicola G.Inno L.Kudritzki R.-P.Matsunaga N.Monelli M.Nonino M.,Sneden C.Storm J.Thevenin F.Tsujimoto T.Zocchi A.2026-07-01T14:00:57Z2023-10-24T08:15:18ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyvariable-starschemical-abundancesspectroscopyvisible-astronomyClassical Cepheids (CCs) are solid distance indicators and tracers of young stellar populations. Dating back to almost one century ago, they have been safely adopted to trace the rotation, the kinematics and the chemical enrichment history of the Galactic thin disk. The main aim of this investigation is to provide iron, oxygen, and sulfur abundances for the largest and most homogeneous sample of Galactic CCs ever analyzed (1118 spectra of 356 objects). The current sample, containing 77 CCs for which spectroscopic metal abundances are provided for the first time, covers a wide range in Galactocentric distances, pulsation modes, and pulsation periods. Optical, high-resolution, and high S/N spectra collected with different spectrographs were adopted to provide homogeneous estimates of the atmospheric parameters (effective temperature, surface gravity, microturbulent velocity) required for abundance determination. Individual distances are based either on trigonometric parallaxes by Gaia DR3 or on distances based near-infrared Period-Luminosity relations. We found that iron and alpha-element radial gradients based on CCs display a well-defined change in the slope for Galactocentric distances larger than ~12kpc. We also found that logarithmic regressions take account for the variation of [X/H] abundances when moving from the inner to the outer disk. Radial gradients for the same elements, but based on open clusters covering a wide range in cluster ages, display similar trends. This means that the flattening in the outer disk is an intrinsic feature of the radial gradients, since it is independent of age. Empirical evidence indicates that the S radial gradient is steeper than the Fe radial gradient. The difference in the slope is a factor of two in the linear fit (-0.081 vs. -0.041dex/kpc) and changes from -1.62 to -0.91 in the logarithmic distance. Moreover, we found that S (explosive nucleosynthesis) is, on average, under-abundant when compared with O (hydrostatic nucleosynthesis). The difference becomes clearer in the metal-poor regime and in dealing with the [O/Fe] and [S/Fe] abundance ratios. We performed a detailed comparison with Galactic chemical evolution models and we found that a constant Star Formation Efficiency for Galactocentric distances larger than 12kpc takes account for the flattening observed in both iron and alpha-elements. To further constrain the impact that predicted S yields for massive stars have on radial gradients, we adopted a "toy model" and we found that the flattening in the outermost regions requires a decrease of a factor of four in the current S predictions. CCs are solid beacons to trace the recent chemical enrichment of young stellar populations. Sulfur photospheric abundances, when compared with other alpha-elements, have the key advantage of being a volatile element. Therefore, stellar S abundances can be directly compared with nebular sulfur abundances in external galaxies.2023A&A...678A.195Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/678/A195CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/283 : RAVE 6th data release (Steinmetz+, 2020)J/AJ/142/136 : Spectroscopy of Cepheids. l=30-250{deg} (Luck+, 2011)J/A+A/566/A37 : Iron abundances for 42 Galactic Cepheids (Genovali+, 2014)J/AJ/156/171 : Cepheid abund.: multiphase results + spatial gradientsJ/MNRAS/508/4047 : 47 classical Cepheids HARPSN@TNG spectroscopyJ/A+A/661/A104 : Physical parameters of classical Cepheids (da Silva+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/678/A195https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/678/A195http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/678/A195https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/678/A195https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/678/A195http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/678/A195GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/678/A195/table1 (Pulsation parameters, literature Fe abundance, and Heliocentric and Galactocentric distances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/678/A195/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/678/A195/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/678/A195/table1?GETtext/xml+votable180.050000true91.6456083326.329219720.0055555555555555565/9482 9807 6/1239 1426 1445 1985 3342 3361 3600 3616 12934 12971 12987 13201 13288 13931 13933 14047 14238 14260 14262 14402 14404 14409 14436 14625 14718 14770 15360 15633 15660 20805 20827 20838 20850 20852 20854 20861-20862 20891 20945 20957-20958 20978 21539 21542 21632 21648 21671-21672 22024 22055 22064 22068-22069 22071 22074 22106 22115 22122 22124 22203 22207 22214 22219 22221 22223 22267 23619 23622 23659-23660 23662 23763 23778 23846 23852 23922 23936 24002 24149 24226 24326 24340 24372 24411 24424 24450 28717 28779 28808 28819 28875 28893 28916 28991 29032 29081 29089 29095 29104 29106 29110 29126 29166 29216 29468 29510 29519 29523 29665 29875 29897 29999 30128 30211 30219 30222 30245 30258 30270 30313 30321-30322 30333 30401 30438 30452 30504 30637 30641 32074 33804 37203 37223 37235 37240 37245 37247 37273 37303 37315 37329-37330 37332 37334 37336 37339-37340 37357 37364 37366 37674 37706 37713 37717 37721 37723 37729 37734 37736 37741 37745-37746 37757 37791 37813 37821 37828-37829 37856 37859 37866-37867 37870 37888 37895 37897 37903-37904 37917 37923 37926-37927 37932 37938 37963 38016-38017 38020 38022-38024 38026 38029 38048-38049 38627 39125 39189 39196 39199 39216-39217 39221 39232 39239 39244-39245 39271 39277 39293 39316-39317 39321 39326 39348 39353 39368 39374 39392 39406 39410 39416 39697 39704 39749-39750 39753-39754 39759 39766 39771 39779 39782 39784 39790 39793-39794 39796 39824 39831 39838 39872-39873 39880 39883 39886-39887 39891-39892 39894 39896 39903 39905 39908 39913 39920 39926 39930 39933 39935 40491 40494 40608 40634 41375 41383 41385 41419 41461 41556 41595 41599 41605 41608 41626 41631 41661 41667 41673-41674 41681 41697-41698 41721-41722 41737 41761-41762 41765 41768 41810 41813 41833 41842 41860 41862 42023 42153 42155-42156 42185 42224 42297 42352 42378 42445 42500 42820 43012-43013 43017 43022-43023 43028 43040-43041 43047 43056-43057 43060 43722https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/678/A195?format=asciiOpticaldefaultJ/A+A/678/A195/table1Pulsation parameters, literature Fe abundance, and Heliocentric and Galactocentric distancesDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainModePulsation modephys.veloc.pulsatint[Fe/H]? Stellar metallicity [Fe/H] from literaturephys.abund.Zfloatnullablee_[Fe/H]? Error in the stellar metallicitystat.error;phys.abund.Fefloatnullabler_[Fe/H]? Reference for metallicity from literature (1)meta.refintnullableXHeliocentric distance projected on the x-axispcpos.cartesian.x;pos.galacticintYHeliocentric distance projected on the y-axispcpos.cartesian.y;pos.galacticintZHeliocentric distance projected on the z-axispcpos.cartesian.z;pos.galacticintRHHeliocentric radial distancepcpos.distance;pos.heliocentricintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid namemeta.id;meta.maincharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainRGGalactocentric radial distancepcpos.distance;pos.galactocentricinte_R? Error in the radial distancepcstat.errorintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharPeriod? Pulsation perioddtime.perioddoublenullableJ/A+A/678/A195/table2Atmospheric parameters and Fe, O, and S abundances for each spectrumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid namemeta.numbercharDatasetSpectroscopic datasetpos.parallax.spectcharMJDModified Julian Datedtime.epochdoubleTeffEffective temperatureKphys.temperature.effectiveintNFeI? Number of FeI lines adoptedmeta.numberintnullablee_TeffError in the effective temperatureKstat.error;phys.temperature.effectiveintlogg? Surface gravitylog(cm.s**-2)phys.gravityfloatnullablevt? Microturbulent velocitykm/sphys.velocfloatnullableFeI? Iron abundance from FeI lines [Fe I/H]phys.abund.Fefloatnullablee_FeI? Error in the FeI abundancestat.errorfloatnullableFeII? Iron abundance from FeII lines [Fe II/H]phys.abund.Fefloatnullablee_FeII? Error in the FeII abundancestat.errorfloatnullableNFeII? Number of FeII lines adoptedmeta.numberintnullableOH? Oxygen abundance from the 6300.3 O line [O/H]phys.abundfloatnullablee_OH? Error in the OI abundancestat.errorfloatnullableSH? Sulfur abundance from the 6757.2 S line [S/H]phys.abundfloatnullablee_SH? Error in the SI abundancestat.errorfloatnullableJ/A+A/678/A195/table3Mean Fe, O, and S abundances for each starNSNumber of spectra with derived S abundancemeta.numberintNFEROSNumber of spectra from FEROSmeta.numberintNHARPSNumber of spectra from HARPSmeta.numberintNUVESNumber of spectra from UVESmeta.numberintNSTELLANumber of spectra from STELLAmeta.numberintNameCepheid namemeta.numbercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFeI? Mean iron abundance from FeI linesphys.abund.Fefloatnullablee_FeI? Error in the mean FeI abundancestat.errorfloatnullableFeII? Mean iron abundance from FeII linesphys.abund.Fefloatnullablee_FeII? Error in the mean FeII abundancestat.errorfloatnullableFeH? Mean iron abundance from FeI, FeII linesphys.abund.Fefloatnullablee_FeH? Error in the mean Fe abundancestat.errorfloatnullables_FeH? Standard deviation of the mean Fe abundancestat.stdev;phys.abund.Fe;stat.meanfloatnullableNFeNumber of spectra with derived Fe abundancemeta.numberintOH? Mean oxygen abundance from the OI linephys.abund;stat.meanfloatnullablee_OH? Error in the mean O abundancestat.errorfloatnullables_OH? Standard deviation of the mean O abundancestat.stdev;phys.abund;stat.meanfloatnullableNONumber of spectra with derived O abundancemeta.numberintSH? Mean sulfur abundance from the SI linephys.abundfloatnullablee_SH? Error in the mean S abundancestat.errorfloatnullables_SH? Standard deviation of the mean S abundancestat.stdev;phys.abund;stat.meanfloatnullable