J/MNRAS/545/F221ivo://CDS.VizieR/J/MNRAS/545/F2216CDSCall S.Griffith T.Hintz E.Ardern S.Scowcroft V.Davidson J.,Boizelle B.2026-03-02T06:25:50Z2026-01-06T06:30:24ZCDS support team

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

cds-question@unistra.frvariable-starsinfrared-sourceschemical-abundancesWe present medium resolution near-infrared spectral measurements of the carbon monoxide (CO) and the cyano radical (CN) features in 12 Galactic classical Cepheids. The pulsation periods of our sample range from 5.5 to 69 days, and the stars studied each had five or more near-IR spectral observations. The CO and CN measurements were used to probe CNO abundances of these stars, and elemental abundance values from the literature were used to identify the trends of [C/N] and [O/N] with CN and CO. To put these measurements in context, we performed stellar atmosphere fitting to obtain estimates of stellar parameters, with a primary focus on effective temperature. Our measurements and temperature estimates show that CN is significantly affected by dredge-up of processed material. We provide discussion as to the potential nature of the recently confirmed classical Cepheid, ET Vul, and connect our near-infrared CO measurements to the mid-infrared period-colour-metallicity relation.2026MNRAS.545f2216Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/545/F2216CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/156/171 : Cepheid abund.: Multiphase results (Luck, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/545/F2216https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/545/F2216http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/545/F2216https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/545/F2216https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/545/F2216http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/545/F2216GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/545/F2216/stars (List of studied Cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/545/F2216/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/545/F2216/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/545/F2216/stars?GETtext/xml+votable180.050000true297.099166727.28650.0055555555555555566/1829 1836 1935 3157 12968 14205 14388 14409 14449 15618 23936 24326https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/545/F2216?format=asciiInfrareddefaultJ/MNRAS/545/F2216/starsList of studied CepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarCepheid namemeta.id;meta.maincharRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Simbad declination (J2000)pos.eq.dec;meta.mainNobsNumber of observations in table B1meta.numberintSimbadSimbad column added by the CDSmeta.ref.urlcharJ/MNRAS/545/F2216/tableb1Phase measurements and fitting results for each Cepheid observationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarCepheid IDmeta.id;meta.maincharPhasePhase from observationtime.phasefloatHJDHeliocentric Julian Datedtime.epochdoubleredchi2Reduced chi square of spectral fittingstat.fit.chi2intTeffEffective temperatureKphys.temperature.effectivefloatloggSurface gravitylog(cm.s**-2)phys.gravityfloatvmicMicroturbulence velocitykm/sphys.veloc.microTurbfloatCOCO indexmagspect.indexfloate_COCO index uncertaintymagstat.errorfloatCNCN indexmagspect.indexfloate_CNCN index uncertaintymagstat.errorfloatPaBPaschen Beta indexmagspect.indexfloate_PaBPaschen Beta index uncertaintymagstat.errorfloatPaDPaschen Delta indexmagspect.indexfloate_PaDPaschen Delta index uncertaintymagstat.errorfloat