A Proper Motions Study of the Globular Cluster NGC 3201
- Department of Physics and Institute of Astronomy, National Tsing-Hua University, Hsin-Chu, Taiwan (China)
- Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 002 (India)
With a high value of heliocentric radial velocity, a retrograde orbit, and suspected to have an extragalactic origin, NGC 3201 is an interesting globular cluster for kinematical studies. Our purpose is to calculate the relative proper motions (PMs) and membership probability for the stars in the wide region of globular cluster NGC 3201. PM based membership probabilities are used to isolate the cluster sample from the field stars. The membership catalog will help address the question of chemical inhomogeneity in the cluster. Archive CCD data taken with a wide-field imager (WFI) mounted on the ESO 2.2 m telescope are reduced using the high-precision astrometric software developed by Anderson et al. for the WFI images. The epoch gap between the two observational runs is ∼14.3 years. To standardize the BVI photometry, Stetson’s secondary standard stars are used. The CCD data with an epoch gap of ∼14.3 years enables us to decontaminate the cluster stars from field stars efficiently. The median precision of PMs is better than ∼0.8 mas yr{sup −1} for stars having V<18 mag that increases up to ∼1.5 mas yr{sup −1} for stars with 18
- OSTI ID:
- 22863114
- Journal Information:
- The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 3 Vol. 153; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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