New metallicities of RR Lyrae stars in ω Centauri

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dc.contributor.authorSollima, A
dc.contributor.authorBorissova, J
dc.contributor.authorCatelan, M
dc.contributor.authorSmith, HA
dc.contributor.authorMinniti, D
dc.contributor.authorCacciari, C
dc.contributor.authorFerraro, FR
dc.date.accessioned2025-01-21T01:06:17Z
dc.date.available2025-01-21T01:06:17Z
dc.date.issued2006
dc.description.abstractWe present new spectroscopic metal abundances for 74 RR Lyrae (RRL) stars in omega Cen obtained with FLAMES. The well-known metallicity spread is visible among the RRL variables. The metal-intermediate (MI) RRL stars ([Fe/H] similar to -1.7) are fainter than the bulk of the dominant metal-poor population ([Fe/H] similar to -1.7), in good agreement with the corresponding zero-age horizontal-branch models with cosmological helium abundance. This result Y = 0.246 conflicts with the hypothesis that the progenitors of the MI RRL stars correspond to the anomalous blue main-sequence stars, which share a similar metallicity but whose properties are currently explained by assuming for them a large helium enhancement. Therefore, in this scenario, the coexistence within the cluster of two different populations with similar metallicities ([Fe/H] similar to -1.7) and different helium abundances has to be considered.
dc.fuente.origenWOS
dc.identifier.eissn1538-4357
dc.identifier.issn0004-637X
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/96127
dc.identifier.wosidWOS:000236143300011
dc.issue.numero1
dc.language.isoen
dc.pagina.finalL46
dc.pagina.inicioL43
dc.revistaAstrophysical journal
dc.rightsacceso restringido
dc.subjectglobular clusters : individual (omega Centauri)
dc.subjectstars : abundances
dc.subjectstars : Population II
dc.subjecttechniques : spectroscopic
dc.titleNew metallicities of RR Lyrae stars in ω Centauri
dc.typeartículo
dc.volumen640
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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