Globular Cluster Abundances from Ca II Triplet Spectroscopy of Member Giants

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Session 50 -- Globular Clusters
Display presentation, Wednesday, 9:20-6:30, Pauley Room

[50.11] Globular Cluster Abundances from Ca II Triplet Spectroscopy of Member Giants

G. S. Da Costa (AAO), T. E. Armandroff (KPNO/NOAO)

Spectroscopy at the Ca II triplet has been obtained of a number of member giants in a sample of globular clusters of current interest. These clusters include NGC 6626 (M28), a cluster with a previously poorly known though moderately metal-poor abundance and disk-like kinematics; Terzan 7, a cluster that may be substantially younger than the majority of globular clusters; and Terzan 8, a distant cluster with no previous spectroscopic abundance determination. The abundances for these clusters are derived from a calibration of Ca II triplet line strengths that covers the entire range of globular cluster abundances. Radial velocities are also derived from the spectra and used to investigate the kinematics of the clusters. For example, despite its metal-rich abundance, Terzan 7 appears to be kinematically a halo object.

Wednesday program listing