Variable Stars in Galactic Globular Clusters
Variable Stars in Galactic Globular Clusters
复制标题
银河球状星团中的变星
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Helen Sawyer Hogg
中科院分区：
文献类型：
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作者：
C. Clement;A. Muzzin;Q. Dufton;Thivya Ponnampalam;John Wang;Jay Burford;Alan Richardson;Tara Rosebery;J. Rowe;Helen Sawyer Hogg
根据到2001年5月为止的文献检索，银河系球状星团中已知的变星大约有3000颗。其中超过2200颗有已知的周期，大多数（大约1800颗）是天琴座RR型。除了天琴座RR星群，还有大约100个食双星、120个SX凤凰变星、60个造父变星（包括II星族、异常造父变星和RV金牛座）和120个SR/红色变星。基本模RR Lyrae变量的平均周期为0.585天，泛音变量的平均周期为0.342天（第一泛音脉冲为0.349天，第二泛音脉冲为0.296天），约30%为泛音脉冲。这些数字表明，银河系球状星团中大约65%的天琴座RR变星属于Oosterhoff I型系统。在Oosterhoff I型星团中，RR Lyrae变量的平均周期似乎与金属丰度相关，因为在金属含量越低的星团中，周期越长。这种相关性在osterhoff II型星团中并不存在。大多数造父变星都聚集在具有蓝色水平分支的星团中。
Based on a search of the literature up to 2001 May, the number of known variable stars in Galactic globular clusters is approximately 3000. Of these, more than 2200 have known periods and the majority (approximately 1800) are of the RR Lyrae type. In addition to the RR Lyrae population, there are approximately 100 eclipsing binaries, 120 SX Phoenicis variables, 60 Cepheids (including Population II Cepheids, anomalous Cepheids and RV Tauri), and 120 SR/red variables. The mean period of the fundamental mode RR Lyrae variables is 0.585 days, for the overtone variables it is 0.342 days (0.349 days for the first-overtone pulsators and 0.296 days for the second-overtone pulsators) and approximately 30% are overtone pulsators. These numbers indicate that about 65% of RR Lyrae variables in Galactic globular clusters belong to Oosterhoff type I systems. The mean period of the RR Lyrae variables in the Oosterhoff type I clusters seems to be correlated with metal abundance in the sense that the periods are longer in the more metal poor clusters. Such a correlation does not exist for the Oosterhoff type II clusters. Most of the Cepheids are in clusters with blue horizontal branches.