NOAO >   Observing Info >   Approved Programs >   2001B-0360

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Proposal Information for 2001B-0360


PI: Ronald Wilhelm, Southwestern University, wilhelmr@southwestern.edu
Address: 1001 East University Ave, Georgetown, TX 78626, USA

CoI: Katherine E. Silverthorne, Southwestern University

Title: Spectroscopy of Tidal Candidate Stars Associated with the Globular Cluster NGC 6934

Abstract: Our project is to obtain spectroscopy of stars in the extended tidal tails of the galactic globular cluster, NGC 6934. The tidal tails where discovered from star count analysis and to date, no kinematic search has been conducted to find actual stars that share the motion of the cluster. NGC 6934 is a prime candidate for such a search because its line-of-sight velocity is 2.3\sigma from the mean of the halo field. This means that finding stars in the regions beyond the normal tidal radius and with velocities equal to the cluster, is sufficient to unambiguously identify stars which are co-moving with the cluster. Spectroscopy of stars within the tidal radius and along the extended tails will be obtained. The results form the extended regions should set constraints on the rate of evaporation of stars from the cluster. Abundance analysis of the cluster and tails will help to establish if peculiarities exist in the extended population. Finally, the fortuitous position of the cluster just below the Galactic plane means a significant number of stars with non-cluster velocities will be members of the halo (giants) or thick disk (dwarfs stars). We will analyze this data to further the understanding of the kinematics of the Galactic field populations.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2001B-0360

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