WIYN OPEN CLUSTER STUDY LII: WIDE-FIELD CCD PHOTOMETRY OF THE OLD OPEN CLUSTER NGC 6819

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/762/1/3· OSTI ID:22167354

Yang, Soung-Chul; Kim, Sang Chul; Kyeong, Jaemann ^[1]; Sarajedini, Ata ^[2]; Deliyannis, Constantine P.

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1. Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)
2. Department of Astronomy, University of Florida, P.O. Box 112055, Gainesville, FL 32611 (United States)

We present a comprehensive photometric study of the old open cluster, NGC 6819, using 1 Degree-Sign Multiplication-Sign 1 Degree-Sign field VI MOSAIC CCD imaging taken with the WIYN 0.9 m telescope. The resultant color-magnitude diagram (CMD) shows a well-developed main sequence (MS) extending from V {approx} 14.5 mag down to our photometric limit of V {approx} 21 mag. Fitting theoretical isochrones with the adopted values of the reddening and metallicity (E(B - V) = 0.14, [Fe/H] = +0.09 dex) to the observed CMD yields a distance modulus of (m - M){sub 0} = 11.93 {+-} 0.10 and an age of {approx}2.6 Gyr for NGC 6819. Our wide-field imaging reveals that NGC 6819 is larger in areal extent (R = 13') than previously thought. The wide field also benefits our estimate of the degree of field star contamination, and ultimately yields improved measurements of the structural parameters (r{sub c} = 2.'80, r{sub t} = 38.'2, and r{sub h} = 7') and tidal mass of the cluster (M {sub tid} = 3542.4 M {sub Sun }). The flattened luminosity and mass functions indicate that NGC 6819 has experienced mass segregation as a result of its dynamical evolution. Our variability study of the cluster blue straggler star (BSS) population using the Welch-Stetson variability index (I {sub WS}) has revealed a number of variable BSS candidates.

• OSTI ID: 22167354
• Journal Information: Astrophysical Journal, Vol. 762, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTRONOMY
ASTROPHYSICS
CHARGE-COUPLED DEVICES
COLOR
DIAGRAMS
ELEMENT ABUNDANCE
HYDROGEN
INDEXES
IRON
LUMINOSITY
MASS
PHOTOMETRY
STAR CLUSTERS
STARS
TELESCOPES