CCD UBV photometry and kinematics of the open cluster NGC 225

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• 作者：Selç ; uk Bilir^a ; ^{sbilir@istanbul.edu.tr" class="auth_mail" title="E-mail the corresponding author} ; Z. Funda Bostancı^a ; Talar Yontan^b ; Tolga Gü ; ver^a ; Volkan Bakış^c ; Tansel Ak^a ; Serap Ak^a ; Ernst Paunzen^d ; Zeki Eker^c
• 关键词：Galaxy ; Open cluster and associations ; Individual ; NGC 225 ; Stars ; Hertzsprung Russell (HR) diagram
• 刊名：Advances in Space Research
• 出版年：2016
• 出版时间：1 November 2016
• 年：2016
• 卷：58
• 期：9
• 页码：1900-1914
• 全文大小：2413 K

文摘

We present the results of CCD UBV   photometric and spectroscopic observations of the open cluster NGC 225. In order to determine the structural parameters of NGC 225, we calculated the stellar density profile in the cluster’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 parameters of the cluster. We calculated the mean radial velocity of the cluster as V_r=-8.3±5.0$V_r=-8.3\pm 5.0$ km s⁻¹ from the optical spectra of eight stars in the cluster’s field. Using the U-B$U-B$ vs B-V$B-V$ 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$E(B-V)=0.151\pm 0.047$ mag and [Fe/H]=-0.11±0.01$[\text{Fe}/\text{H}]=-0.11\pm 0.01$ dex, respectively. We fitted the colour-magnitude diagrams of NGC 225 with the PARSEC isochrones and derived the distance modulus, distance and age of the cluster as μ_V=9.3±0.07${\mu }_V=9.3\pm 0.07$ mag, d=585±20$d=585\pm 20$ pc and t=900±100$t=900\pm 100$ Myr, respectively. We also estimated the galactic orbital parameters and space velocity components of the cluster and found that the cluster has a slightly eccentric orbit of e=0.07±0.01$e=0.07\pm 0.01$ and an orbital period of P_orb=255±5$P_{\mathit{orb}}=255\pm 5$ Myr.