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dc.creatorMarino, A. F.en_US
dc.creatorSneden, Christopheren_US
dc.creatorKraft, R. P.en_US
dc.creatorWallerstein, G.en_US
dc.creatorNorris, J. E.en_US
dc.creatorDa Costa, G.en_US
dc.creatorMilone, A. P.en_US
dc.creatorIvans,, IIen_US
dc.creatorGonzalez, G.en_US
dc.creatorFulbright, J. P.en_US
dc.creatorHilker, M.en_US
dc.creatorPiotto, G.en_US
dc.creatorZoccali, M.en_US
dc.creatorStetson, P. B.en_US
dc.date.accessioned2016-04-22T19:48:51Z
dc.date.available2016-04-22T19:48:51Z
dc.date.issued2011-08en
dc.identifierdoi:10.15781/T2X51J
dc.identifier.citationMarino, A. F., Christopher Sneden, R. P. Kraft, G. Wallerstein, J. E. Norris, G. Da Costa, A. P. Milone et al. >The two metallicity groups of the globular cluster M 22: a chemical perspective.> Astronomy & Astrophysics, Vol. 532 (Aug., 2011): A8.en_US
dc.identifier.issn0004-6361en_US
dc.identifier.urihttp://hdl.handle.net/2152/34564
dc.description.abstractWe present a detailed chemical composition analysis of 35 red giant stars in the globular cluster M22. High resolution spectra for this study were obtained at five observatories, and analyzed in a uniform manner. We have determined abundances of representative light proton-capture, alpha, Fe-peak and neutron-capture element groups. Our aim is to better understand the peculiar chemical enrichment history of this cluster, in which two stellar groups are characterized by a different content in iron, neutron capture elements Y, Zr and Ba, and alpha element Ca. The principal results of this study are: (i) substantial star-to-star metallicity scatter (-2.0 less than or similar to [Fe/H] less than or similar to -1.6); (ii) enhancement of s-process/r-process neutron-capture abundance ratios in a fraction of giants, positively correlated with metallicity; (iii) sharp separation between the s-process-rich and s-process-poor groups by [La/Eu] ratio; (iv) possible increase of [Cu/Fe] ratios with increasing [Fe/H], suggesting that this element also has a significant s-process component; and (v) presence of Na-O and C-N anticorrelations in both the stellar groups.en_US
dc.description.sponsorshipNational Aeronautics and Space Administrationen_US
dc.description.sponsorshipNational Science Foundationen_US
dc.description.sponsorshipCanadian Space Agencyen_US
dc.description.sponsorshipFondecyt Regular 1085278en_US
dc.description.sponsorshipMideplan Milky Way Millennium Nucleus P07-021-Fen_US
dc.description.sponsorshipUS National Science Foundation AST 09-08978 Australian Research Council DP0984924 20075TP5K9en_US
dc.language.isoEnglishen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjecttechniques: spectroscopicen_US
dc.subjectstars: abundancesen_US
dc.subjectstars: population iien_US
dc.subjectglobular clusters: individual: m 22 (ngc 6656)en_US
dc.subjectmultiple stellar populationsen_US
dc.subjectstar abundance variationsen_US
dc.subjects-processen_US
dc.subjectnucleosynthesisen_US
dc.subjectneutron-capture elementsen_US
dc.subjectdouble subgiant branchen_US
dc.subjectcentauri ngc 5139en_US
dc.subjectred giant branchen_US
dc.subjectmetal-poor starsen_US
dc.subjectomega-centaurien_US
dc.subjectmassive starsen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleThe Two Metallicity Groups Of The Globular Cluster M22: A Chemical Perspectiveen_US
dc.typeArticleen_US
dc.description.departmentAstronomyen_US
dc.identifier.doi10.1051/0004-6361/201116546en_US
dc.contributor.utaustinauthorSneden, Christopheren_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US


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