论文标题
三个中级开放群集NGC 381，NGC 2360和伯克利68的光度和运动学研究
Photometric and Kinematic study of the three intermediate age open clusters NGC 381, NGC 2360, and Berkeley 68
论文作者
论文摘要
我们提出了三个中级开放型星团NGC 381，NGC 2360和Berkeley 68（BE 68）的UBVRCIC光度法研究。我们使用最近发布的Gaia DR2适当运动来检查恒星的簇成员资格，并在这三个簇中获得总共116、332和264个成员恒星。 E（b-v）= 0.36 +/- 0.04、0.08 +/- 0.03和0.52 +/- 0.04 mag在这些簇的方向上发现了我们观察到NGC 381的异常变化的方向，我们适合了ngc 381。 8.95 +/- 0.05，以及9.25 +/- 0.05年，距离为957 +/- 152、982 +/- 132和2554 +/- 387 pc，用于clusters ngc 381，ngc 2360，ngc 2360和Be 68。簇NGC 2360和BE68中的单个MF斜率。为了研究MF斜率可能存在空间变化，我们在这些簇的内部和外部区域分别估计斜率，并注意到外部区域的陡峭斜率更陡峭。这些簇的动态研究揭示了其内部区域中低质量恒星的缺乏，表明所有这些簇中的质量分离过程。对于簇NGC 381，NGC 2360和68，获得了48.5、78.9和87.6 MYR的松弛时间，远低于它们各自的年龄。这表明所有簇都动态放松。
We present UBVRcIc photometric study of three intermediate age open star clusters NGC 381, NGC 2360, and Berkeley 68 (Be 68). We examine the cluster membership of stars using recently released Gaia DR2 proper motions and obtain a total of 116, 332, and 264 member stars in these three clusters. The mean reddening of E(B - V) = 0.36+/-0.04, 0.08+/-0.03, and 0.52+/-0.04 mag are found in the direction of these clusters where we observe an anomalous reddening towards NGC 381. We fitted the solar metallicity isochrones to determine age and distance of the clusters which are found to be log(Age) = 8.65+/-0.05, 8.95+/-0.05, and 9.25+/-0.05 yr with the respective distance of 957+/-152, 982+/-132, and 2554+/-387 pc for the clusters NGC 381, NGC 2360, and Be 68. A two-stage power law in the mass function (MF) slope is observed in the cluster NGC 381, however, we observe only a single MF slope in the clusters NGC 2360 and Be68. To study a possible spatial variation in the slope of MF we estimate slopes separately in the inner and the outer regions of these clusters and notice a steeper slope in outer region. The dynamic study of these clusters reveals deficiency of low-mass stars in their inner regions suggesting the mass segregation process in all these clusters. The relaxation times of 48.5, 78.9, and 87.6 Myr are obtained for the clusters NGC 381, NGC 2360, and Be 68, respectively which are well below to their respective ages. This suggests that all the clusters are dynamically relaxed.
