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High resolution infrared spectra of NGC 6342 and NGC 6528: two moderately reddened Bulge Globular Clusters

L. Origlia·E. Valenti·R. M. Rich
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Abstract

Using the NIRSPEC spectrograph at Keck II, we have obtained infrared echelle spectra covering the range 1.5-1.8 micron for the moderately reddened bulge globular clusters NGC 6342 and NGC 6528, finding [Fe/H]= -0.60 and -0.17 dex, respectively. We measure an average alpha-enhancement of approx +0.33 dex in both clusters, consistent with previous measurements on other metal rich bulge clusters, and favoring the scenario of a rapid bulge formation and chemical enrichment. We also measure very low 12C/13C isotopic ratios (approx 5 in NGC 6342 and approx 8 in NGC 6528), suggesting that extra-mixing mechanisms due to cool bottom processing are at work during evolution along the Red Giant Branch.

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L. Origlia, E. Valenti, R. M. Rich. 2004-10-21. High resolution infrared spectra of NGC 6342 and NGC 6528: two moderately reddened Bulge Globular Clusters. https://doi.org/10.1111/j.1365-2966.2004.08529.x

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