star2000 - Dynamics of Star Clusters and the Milky Way

Deep BV CCD Photometry of the Metal-Rich Globular Cluster M71

H.-S. Yim, M.-S. Chun, Y.-I. Byun
Department of Astronomy
Yonsei University
134 Shinchondong
Seodaemungu
120-749 Seoul, Korea

Deep BV photometry for about 15000 stars in the globular cluster M71 has been obtained from the 2.2m University Hawaii Telescope using 2k CCD. The frames cover a 7.5' x 7.5' region of the cluster center through 220" (about 7 core radii). A complete color-magnitude diagram(CMD) from the upper red-giant branch to the lower main sequence (V_{limit} ~ 22; approximately 5 mag below the main-sequence turnoff) has been constructed. From the fitting of the CMD fiducial sequence to the New Yale Isochrone and the similar metallicity globular cluster 47 Tuc, we estimated the absolute and relative ages of this "disk population" globluar cluster.

A luminosity function to M_{v} ~ 8.3 for the cluster main-sequence has been derived. Applying several theoritical mass-luminosity relations, we derived mass function of M71. We discuss the implications of this on recent HST results about low mass main-sequence stars' lumisoty function and on dynamical evolution of the globular cluster.

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