CCD UBV Photometry and Kinematics of the Open Cluster NGC
CCD UBV Photometry and Kinematics of the Open Cluster NGC 225 Sel¸cuk Bilira,∗, Z. Funda Bostancıa, Talar Yontanb, Tolga G¨uvera, Volkan Bakı¸sc, Tansel Aka, Serap Aka, Ernst Paunzend, Zeki Ekerc aIstanbul University, Faculty of Science, Department of Astronomy and Space Sciences, 34119 University, Istanbul, Turkey bIstanbul University, Graduate School of Science and Engineering, Department of Astronomy and Space Sciences, 34116, Beyazıt, Istanbul, Turkey cDepartment of Space Sciences and Technologies, Faculty of Sciences, Akdeniz University, Antalya 07058, Turkey dDepartment of Theoretical Physics and Astrophysics, Masaryk University, Kotl´a˘rsk´a2, 611 37 Brno, Czech Republic Abstract We present the results of CCD UBV photometric and spectroscopic obser- vations of the open cluster NGC 225. In order to determine the structural parameters of NGC 225, we calculated the stellar density profile in the clus- ter’s field. We estimated the probabilities of the stars being physical members of the cluster using the existing astrometric data. The most likely members of the cluster were used in the determination of the astrophysical parame- ters of the cluster. We calculated the mean radial velocity of the cluster as −1 Vr = 8.3 5.0 km s from the optical spectra of eight stars in the cluster’s field.− Using± the U B vs B V two-colour diagram and UV excesses of the F- − − G type main-sequence stars, the reddening and metallicity of NGC 225 were inferred as E(B V )=0.151 0.047 mag and [Fe/H]= 0.11 0.01 dex, respectively. We− fitted the colour-magnitude± diagrams of NGC− 225± with the arXiv:1606.08608v1 [astro-ph.GA] 28 Jun 2016 PARSEC isochrones and derived the distance modulus, distance and age of the cluster as µ =9.3 0.07 mag, d = 585 20 pc and t = 900 100 Myr, V ± ± ± respectively.
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