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A Comparison of Copper Abundances in Globular Cluster and Halo Field Giant Stars

Research paper by Jennifer Simmerer, Christopher Sneden, Inese I. Ivans, Robert P. Kraft, Matthew D. Shetrone, Verne V. Smith

Indexed on: 07 Mar '03Published on: 07 Mar '03Published in: Astrophysics



Abstract

We derive [Cu/Fe] for 117 giant stars in ten globular clusters (M3, M4, M5, M10, M13, M15, M71, NGC 7006, NCG 288, and NGC 362) and find that globular cluster Cu abundances appear to follow [Cu/Fe] trends found in the field. This result is interesting in light of recent work which indicates that the globular cluster Omega Centauri shows no trend in [Cu/Fe] with [Fe/H] over the abundance range -2.0 <[Fe/H]< -0.8. Of particular interest are the two clusters M4 and M5. While at a similar metallicity ([Fe/H] ~- 1.2), they differ greatly in some elemental abundances: M4 is largely overabundant in Si, Ba, and La compared to M5. We find that it is also overabundant in Cu with respect to M5, though this overabundance is in accord with [Cu/Fe] ratios found in the field.