J/A+A/703/A228ivo://CDS.VizieR/J/A+A/703/A228CDSMarconi M.Molinaro R.Ripepi V.De Somma G.Sicignano T.Deka M.,Di Criscienzo M.Luongo E.Musella I.Trentin E.2026-03-02T06:25:50Z2025-11-28T09:54:24ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomytrigonometric-parallaxType II Cepheids are pulsating stars that can be used as standard candles for old stellar populations due to their characteristic Period-Luminosity and Period-Luminosity-Colour relations. They are traditionally divided in 3 sub-classes, namely BL Her, W Vir and RV Tauri.In this paper we focus on the first two sub-classes, to provide a new theoretical scenario and develop tools and relations to be adopted in distance scale and old stellar populations studies. We built new non-linear convective pulsation models of Type II Cepheids, computed along selected stellar evolution tracks and spanning a wide range of pulsation period and stellar parameters. Three chemical compositions have been taken into account, namely Z=0.0001 Y=0.245, Z=0.001 Y=0.245, and Z=0.01 Y=0.26. For each assumed Z and Y, models were computed following stellar evolution predictions for of-zero-age horizontal-branch evolution of stellar masses lower than typical RR Lyrae stars, crossing the classical instability strip as BL Her or W Vir pulsating stars. A new theoretical prediction for the instability strip boundaries of these classes of variable stars has been obtained together with their dependence on metal abundance. The predicted light and radial-velocity curves were computed along the evolution inside the strip, showing how the amplitude and the morphology are affected by the position relative to the edges and by the luminosity and mass values. The transformation of bolometric light curves into various photometric systems allowed us to provide new theoretical period-luminosity and period-Wesenheit relations for BL Her and W Vir. These relations are found to be consistent with previously published RR Lyrae model results but with a smaller metallicity dependence. Moreover, the application of the inferred theoretical relations to Magellanic and Galactic Type II Cepheid data provides results in good agreement with some independent distance estimates in the literature.2025A&A...703A.228Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/703/A228CatalogResearchIsServedByTAP 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/703/A228https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/703/A228http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/703/A228https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/703/A228https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/703/A228http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/703/A228GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/703/A228/table4 (Adopted Galactic Type II Cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A228/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A228/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A228/table4?GETtext/xml+votable180.050000true298.260743626.06883170.0055555555555555566/1861 2863 3472 3781 6386 6811 9281 11792 12321 12685 12872 12904 14378 14401 14480 14562 15138 15212 15726 22120 22164 23332 24503 28696 28757 28765 28779 28838 28871 28940-28941 28964 28973 29150 29289 29652 29758 29852 29881 30221 30239 30244 30398 30553 30596 30637 30870 31019 31192 31778 31792 31862 32052 32124 32170 32531 32739 37244 37650 38443 38596 39158 39769 39933 40167 40535 40627 41102 41186 41311 41313 41413 41455 41611 41719 41726 42022 42046 42050 42151 42602 42713 42898 42957 43026 43046 43133 43153 43411 43656 44176 44786 45720 47127 47168 47708 47852 47866 47868https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/703/A228?format=asciiOpticaldefaultJ/A+A/703/A228/table1The structural parameters of all computed modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintZMetal contentsrc.redshiftdoubleYHelium contentphys.abund.YfloatMassMasssolMassphys.massfloatlogLLuminositylog(solLum)phys.luminosityfloatTeffEffective temperatureKphys.temperature.effectiveintPerPulsational perioddtime.perioddoubleJ/A+A/703/A228/table4Adopted Galactic Type II CepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDVariable namemeta.id;meta.maincharClassVariable Classmeta.code;src.varcharPerPerioddtime.periodfloatplxcorrParallax correction from Lindegreen et al., 2021A&A...649A...4Larith.factorfloatplxDR3Gaia DR3 parallaxmaspos.parallax.trigfloate_plxDR3Gaia DR3 parallax errormasstat.errorfloatplxteoZ0.0001Theoretical parallax for Z=0.0001masstat.paramfloate_plxteoZ0.0001Theoretical parallax error for Z=0.0001masstat.errorfloatplxteoZ0.001Theoretical parallax for Z=0.001masstat.paramfloate_plxteoZ0.001Theoretical parallax error for Z=0.001masstat.errorfloatplxteoZ0.01Theoretical parallax for Z=0.01masstat.paramfloate_plxteoZ0.01Theoretical parallax error for Z=0.01masstat.errorfloatSimbadNameSimbad column added by the CDSmeta.idcharnullable_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.main