论文标题
CCD \ emph {vi}极差的球形群集M92的时间序列：重新审视其可变恒星种群
CCD \emph{VI} time-series of the extremely metal poor globular cluster M92: revisiting its variable star population
论文作者
论文摘要
我们提出了\ emph {vi} ccd的时间序列光度法的分析。研究集群的可变星人群，目的是修改其分类，标识，频谱，并选择父母群集金属性和距离的指标。 RR Lyrae光曲线的傅立叶分解导致估计平均值[Fe/H] $ _ {\ rm Spec} = -2.20 \ pm 0.18 $，$ 8.3 \ pm0.2 $ kpc的距离。报告了四个新变量；一个RRD（V40），多模SX PHE（V41），SR（V42）和一个RRC（F1）很可能不是群集成员。 V7的AC性质已得到证实。 RRC星V11的双重模式性质尚未确认，其幅度调制很可能是由于Blazhko效应所致。在已知的RRC变量V13中发现了两种模式。有人认为，以前被归类为rrab的变量V30实际上是不属于群集的BL雌雄同体。利用$ GAIA $ -DR2适当的动作，我们在集群领域确定了5012星，这很可能是群集成员，并且我们拥有光度法，从而可以生产精制的颜色 - 磁性图。这也使我们能够识别一些不属于群集的变量星。 HB上的RR Lyrae脉动模式通过第一个泛音红色边缘干净地分离，这是所有OO II型簇中的共同特征。
We present an analysis of \emph{VI} CCD time-series photometry of the Oo II type globular cluster M92. The variable star population of the cluster is studied with the aim of revising their classifications, identifications, frequency spectra and to select indicators of the parental cluster metallicity and distance. The Fourier decomposition of RR Lyrae light curves lead to the estimation of mean [Fe/H]$_{\rm spec}=-2.20\pm 0.18$, and distance of $8.3\pm0.2$ kpc. Four new variables are reported; one RRd (V40), a multimode SX Phe (V41), a SR (V42) and one RRc (F1) that is most likely not a cluster member. The AC nature of V7 is confirmed. The double mode nature of the RRc star V11 is not confirmed and its amplitude modulations are most likely due to the Blazhko effect. Two modes are found in the known RRc variable V13. It is argued that the variable V30, previously classified as RRab is, in fact, an BL Her-type star not belonging to the cluster. Making use of the $Gaia$-DR2 proper motions, we identified 5012 stars in the field of the cluster, that are very likely cluster members, and for which we possess photometry, enabling the production of a refined Colour-Magnitude Diagram. This also allowed us to identify a few variable stars that do not belong to the cluster. The RR Lyrae pulsation modes on the HB are cleanly separated by the first overtone red edge, a common feature in all Oo II type clusters.
