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    CCD UBV and Gaia DR3 based analysis of NGC 189, NGC 1758 and NGC 7762 open clusters
    (Elsevier Sci Ltd, 2023) Yontan, Talar; Bilir, Selcuk; Cakmak, Hikmet; Raul, Michel; Banks, Timothy; Soydugan, Esin; Canbay, Remziye
    This paper presents photometric, astrometric, and kinematic analyses of the open clusters NGC 189, NGC 1758 and NGC 7762 based on CCD UBV photometric and Gaia Data Release 3 (DR3) data. According to membership analyses, we identified 32, 57 and 106 most probable member stars with membership probabilities P >= 0:5 in NGC 189, NGC 1758 and NGC 7762, respectively. The color excesses and photometric metallicities of each cluster were determined separately using UBV two-color diagrams. The color excess E(B - V) is 0: 590 +/- 0:023 mag for NGC 189, 0:310 +/- 0:022 mag for NGC 1758 and 0:640 +/- 0:017 mag for NGC 7762. The photometric metallicity [Fe/H] is -0:08 +/- 0:03 dex for both NGC 189 and NGC 1758, and -0:12 +/- 0:02 dex for NGC 7762. Distance moduli and ages of the clusters were obtained by comparing PARSEC isochrones with the color-magnitude diagrams constructed from UBV and Gaia photometric data. During this process, we kept as constant color excess and metallicity for each cluster. The estimated isochrone distance is 1201 +/- 53 pc for NGC 189, 902 +/- 33 pc for NGC 1758 and 911 +/- 31 pc for NGC 7762. These are compatible with the values obtained from trigonometric parallax. Ages of the clusters are 500 +/- 50 Myr, 650 +/- 50 Myr and 2000 +/- 200 Myr for NGC 189, NGC 1758 and NGC 7762, respectively. Galactic orbit integration of the clusters showed that NGC 1758 completely orbits outside the solar circle, while NGC 189 and NGC 7762 enter the solar circle during their orbits. (c) 2023 COSPAR. Published by Elsevier B.V. All rights reserved.
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    Photometric and Kinematic Studies of Open Clusters Ruprecht 1 and Ruprecht 171
    (Wiley-V C H Verlag Gmbh, 2024) Cakmak, Hikmet; Yontan, Talar; Bilir, Selcuk; Banks, Timothy S.; Michel, Raul; Soydugan, Esin; Koc, Seliz
    This study outlines a detailed investigation using CCD UBV and Gaia DR3 data sets of the two open clusters Ruprecht 1 (Rup-1) and Ruprecht 171 (Rup-171). Fundamental astrophysical parameters such as color excesses, photometric metallicities, ages, and isochrone distances were based on UBV-data analyses, whereas membership probability calculations, structural and astrophysical parameters, as well as the kinematic analyses were based on Gaia DR3-data. We identified 74 and 596 stars as the most probable cluster members with membership probabilities over 50% for Rup-1 and Rup-171, respectively. The color excesses E(B-V) were obtained as 0.166 +/- 0.022 and 0.301 +/- 0.027 mag for Rup-1 and Rup-171, respectively. Photometric metallicity analyses were performed by considering F-G type main-sequence member stars and found to be [Fe/H]=-0.09 +/- 0.16 and [Fe/H]=-0.20 +/- 0.20 dex for Rup-1 and Rup-171, respectively. Ages and distances were based on both UBV and Gaia-data analyses; according to isochrone-fitting these values were estimated to be t=580 +/- 60 Myr, d=1469 +/- 57 pc for Rup-1 and t=2700 +/- 200 Myr, d=1509 +/- 69 pc for Rup-171. The present-day mass function slope of Rup-1 was estimated as 1.26 +/- 0.32 and Rup-171 as 1.53 +/- 1.49. Galactic orbit integration analyses showed that both of the clusters might be formed outside the solar circle.