标题： 低振幅变星：区分RR Lyrae星与食双星 显示英文标题

标题： Low-Amplitude Variables: Distinguishing RR Lyrae stars from Eclipsing Binaries

摘要： 识别和分类低振幅变星并不容易，但正确进行分类很重要。我们使用测光和光谱学对Akerlof等人(2002)区域中246平方度的部分区域的低振幅变星进行分类。Akerlof和合作者发现，在他们2000平方度的测试区域中，38%的RR Lyrae恒星是RR1（类型c）。这表明这些RR Lyrae恒星属于Oosterhoff II型群体，而它们的周期分布主要是Oosterhoff I型。我们的观测支持他们对RR0（类型ab）的分类，然而，他们分类为RR1（类型c）的7颗恒星中有6颗是食双星。我们的分类得到了光谱金属丰度、线宽化和银河系旋转测量的支持。我们的246平方度区域包含16颗比m_R = 14.5更亮的RR Lyrae恒星；其中只有4颗是RR1（类型c）。这与周期分布一致，表明这是一个Oosterhoff I型群体。 显示英文摘要

摘要： It is not easy to identify and classify low-amplitude variables, but it is important that the classification is done correctly. We use photometry and spectroscopy to classify low-amplitude variables in a 246 deg^2 part of the Akerlof et al. (2002) field. Akerlof and collaborators found that 38% of the RR Lyrae stars in their 2000 deg^2 test field were RR1 (type c). This suggests that these RR Lyrae stars belong to an Oosterhoff Type II population while their period distribution is primarily Oosterhoff Type I. Our observations support their RR0 (type ab) classifications, however 6 of the 7 stars that they classified as RR1 (type c) are eclipsing binaries. Our classifications are supported by spectroscopic metallicities, line-broadening and Galactic rotation measurements. Our 246 deg^2 field contains 16 RR Lyrae stars that are brighter than m_R = 14.5; only four of these are RR1 (type c). This corresponds to an Oosterhoff Type I population in agreement with the period distribution.