Type II Cepheids: Evidence for Na-O anticorrelation for BL Her type stars?

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dc.contributor.authorKovtyukh V.
dc.contributor.authorYegorova I.
dc.contributor.authorAndrievsky S.
dc.contributor.authorKorotin S.
dc.contributor.authorSaviane I.
dc.contributor.authorLemasle B.
dc.contributor.authorChekhonadskikh F.
dc.contributor.authorBelik S.
dc.date.accessioned2022-07-29T22:34:20Z
dc.date.available2022-07-29T22:34:20Z
dc.date.issued2018-06
dc.descriptionIndexación Scopuses
dc.description.abstractThe chemical composition of 28 Population II Cepheids and one RR Lyrae variable has been studied using high-resolution spectra. The chemical composition of W Vir variable stars (with periods longer than 8 d) is typical for the halo and thick disc stars. However, the chemical composition of BL Her variables (with periods of 0.8-4 d) is drastically different, although it does not differ essentially from that of the stars belonging to globular clusters. In particular, the sodium overabundance ([Na/Fe] ≈ 0.4) is reported for most of these stars, and the Na-O anticorrelation is also possible. The evolutionary tracks for BL Her variables (with a progenitor mass value of 0.8 solar masses) indicate that mostly helium-overabundant stars (Y = 0.30-0.35) can fall into the instability strip region. We suppose that it is the helium overabundance that accounts not only for the existence of BL Her variable stars but also for the observed abnormalities in the chemical composition of this small group of pulsating variables. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.es
dc.description.urihttps://academic-oup-com.recursosbiblioteca.unab.cl/mnras/article/477/2/2276/4935186
dc.identifier.citationMonthly Notices of the Royal Astronomical Society Volume 477, Issue 2, Pages 2276 - 228521 June 2018es
dc.identifier.doi10.1093/mnras/sty671
dc.identifier.issn00358711
dc.identifier.urihttps://repositorio.unab.cl/xmlui/handle/ria/23377
dc.language.isoenes
dc.publisherOxford University Presses
dc.rights.licenseCC BY 4.0
dc.subjectPeriodes
dc.subjectMagellanic Cloudses
dc.subjectGlobular Clusterses
dc.subjectChemical compositionses
dc.subjectAnticorrelationes
dc.subjectCepheidses
dc.titleType II Cepheids: Evidence for Na-O anticorrelation for BL Her type stars?es
dc.typeArtículoes
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