A double stellar generation in the globular cluster NGC 6656 (M 22) Two stellar groups with different iron and <i>s</i>-process element abundances

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dc.contributor.authorMarino, A. F.
dc.contributor.authorMilone, A. P.
dc.contributor.authorPiotto, G.
dc.contributor.authorVillanova, S.
dc.contributor.authorBedin, L. R.
dc.contributor.authorBellini, A.
dc.contributor.authorRenzini, A.
dc.date.accessioned2025-01-21T00:07:59Z
dc.date.available2025-01-21T00:07:59Z
dc.date.issued2009
dc.description.abstractWe present a chemical abundance analysis based on high resolution UVES spectra of seventeen bright giant stars in the Globular Cluster (GC) M 22. We obtained an average iron abundance of [Fe/H] = -1.76 +/- 0.02 (internal errors only) and an alpha enhancement of 0.36 +/- 0.04 (internal errors only). Na and O, and Al and O follow the well known anticorrelations found in many other GCs. We identified two groups of stars with significantly different abundances of the s-process elements Y, Zr, and Ba. The relative numbers of the two group members are very similar to the ratio of the number of stars in the two sub giant branches (SGB) of M 22. Y and Ba abundances do not correlate with Na, O, and Al. The s-element rich stars are also richer in iron and have higher Ca abundances. The results from high resolution spectra were confirmed by analyses of lower resolution GIRAFFE spectra of fourteen additional M 22 stars. The analyses of the GIRAFFE spectra also show that the Eu - a pure r-process element - abundance is not related to the iron content. We discuss the chemical abundance pattern of M 22 stars in the context of GC multiple stellar populations phenomenon.
dc.fuente.origenWOS
dc.identifier.doi10.1051/0004-6361/200911827
dc.identifier.eissn1432-0746
dc.identifier.issn0004-6361
dc.identifier.urihttps://doi.org/10.1051/0004-6361/200911827
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/95651
dc.identifier.wosidWOS:000270907100015
dc.issue.numero3
dc.language.isoen
dc.pagina.final1113
dc.pagina.inicio1099
dc.revistaAstronomy & astrophysics
dc.rightsacceso restringido
dc.subjectstars: abundances
dc.subjectgalaxy: globular clusters: individual: NGC 6656
dc.titleA double stellar generation in the globular cluster NGC 6656 (M 22) Two stellar groups with different iron and <i>s</i>-process element abundances
dc.typeartículo
dc.volumen505
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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