A CCD Photometric Survey of Variable Stars in the Field of NGC 188
A CCD Photometric Survey of Variable Stars in the Field of NGC 188
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DOI：
10.1086/338846
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发表时间：
2002-03
期刊：
影响因子：
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通讯作者：
Xiaobin Zhang;L. Deng;B. Tian;Xu Zhou
中科院分区：
文献类型：
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作者：
Xiaobin Zhang;L. Deng;B. Tian;Xu Zhou
介绍了最近对覆盖旧疏散星团 NGC 188 的 1° 视野中的变量进行 CCD 光度测量的结果。五晚共识别出16个短周期变量，其中8个为节目领域新变量。通过采用相色散最小化方法，确定了八个新变量中的七个的周期。根据光变曲线的行为、色星等图中的位置以及自行运动的结果，讨论了所有这些变星的主要属性、分类和隶属关系。在这 8 个新天体中，有 6 个是 W UMa 双星，其中 1 个肯定是该星团的成员，2 个可能是该星团的成员。发现了一颗轨道周期超过1天的分离或半分离食双星，这可能是一颗星团星。此外，还检测到一颗具有特殊光变曲线的场星，可以将其归类为RRd型变星。此外，根据我们的观察，给出了八个旧变量的修订后的基本数据。 V8可归类为光变大于0.2星等的RS CVn型恒星。
The results of a recent CCD photometry survey of variables in a 1° field covering the old open cluster NGC 188 are presented. A total of 16 short-period variables were identified during five nights, among which eight are new variables in the program field. By adopting the method of phase-dispersion minimization, the periods for seven of the eight new variables are determined. The main properties, the classifications, as well as the memberships are discussed for all of these variable stars, based on the behavior of light curves, the locations in the color-magnitude diagram, and the results of proper motions. Among the eight new objects, six are W UMa binaries, in which one definitely is and two probably are members of the cluster. A detached or semidetached eclipsing binary with an orbital period longer than 1 day is found, which is a likely cluster star. In addition, a field star with a peculiar light curve is detected, which can be classified as a RRd–type variable. Moreover, revised basic data for the eight old variables are given according to our observations. V8 can be classified as an RS CVn–type star with light variations larger than 0.2 mag.