A Comprehensive Catalog of Variable Stars in the Field of 47 Tucanae
A Comprehensive Catalog of Variable Stars in the Field of 47 Tucanae
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DOI：
10.1086/422433
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发表时间：
2004-05
期刊：
影响因子：
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通讯作者：
D. Weldrake;P. Sackett;T. Bridges;K. Freeman
中科院分区：
文献类型：
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作者：
D. Weldrake;P. Sackett;T. Bridges;K. Freeman
我们提出了一个全面的搜索结果，在球状星团47 Tuccenda恒星的变化。我们使用赛丁泉天文台的斯特罗姆洛山40英寸（1米）望远镜和V + R组合滤光器，在以星团为中心的52′ × 52′视场内探测到了100颗变星。该项目的主要目的是在该星团中寻找凌日的“热木星”行星，其结果将在另一篇论文中讨论。本文给出了所探测到的变星的V + R光变曲线和初步研究结果，其中包括28个食双星（21个接触双星和7个分离系统），45颗RR型天琴座星（其中41颗属于小麦哲伦云，4颗似乎属于银河晕）和20颗K巨星长周期变星（LPV）。我们还发现了四颗盾牌座δ星，一颗I型造父变星和一颗II型造父变星。一个变量似乎是一个可能的尘埃笼罩的SMC星星与短周期的脉动。在这100个变量中，有69个是新发现的。我们的食双星样本表明一个明确的径向分离的周期，包括两个双星，似乎是低光度恒星同伴的轨道。其中一颗天琴座RR型星星显示出具有显著规律性的Blazhko效应。这些先前已知的变量与Kaluzny及其同事的一项研究交叉识别。与以前的研究一致，这项工作表明，与其他研究区域相比，47 Tuc中可检测到的变星（特别是接触双星）的相对频率非常低。从我们的样品中估算出小麦哲伦云的距离模量为18.93±0.24，47 Tuc的距离模量为13.14±0.25，与以前发表的值一致。这里提供的总数据库包含43，067颗Tuc场恒星的V和I测光（13.0 <$V <$21.0），沿着33颗夜晚V + R光变曲线和109，866颗恒星的天体测量（14.5 <$V <$22.5）。
We present the results of a comprehensive search for stellar variability in the globular cluster 47 Tucanae. Using the Mount Stromlo 40 inch (1 m) telescope at Siding Spring Observatory and a combined V + R filter, we have detected 100 variable stars across a 52′ × 52′ field centered on the cluster. The main aim of this project is to search for transiting "hot Jupiter" planets in this cluster, the results of which shall be discussed in a separate paper. Here we present the V + R light curves and preliminary investigations of the detected variable stars, which comprise 28 eclipsing binaries (21 contact binaries and 7 detached systems), 45 RR Lyrae stars (41 of which belong to the Small Magellanic Cloud and 4 seemingly to the Galactic halo), and 20 K-giant long-period variables (LPVs). We also detected four δ Scuti stars, one type I Cepheid, and one type II Cepheid. One variable appears to be a possible dust-enshrouded SMC star with a short-period pulsation. Of these 100 variables, 69 are new discoveries. Our eclipsing binary sample indicates a clear radial segregation in period and includes two binaries that are seemingly orbited by low-luminosity stellar companions. One RR Lyrae star shows a Blazhko effect with remarkable regularity. Those variables previously known are cross-identified with a study by Kaluzny and coworkers. In agreement with previous studies, this work shows that the relative frequency of detectable variable stars (particularly contact binaries) in 47 Tuc is very low compared to other studied regions. Distance moduli of 18.93±0.24 for the Small Magellanic Cloud and 13.14±0.25 for 47 Tuc have been estimated from our sample and are in agreement with values previously published. The total database presented here contains V and I photometry for 43,067 47 Tuc field stars (13.0 ⩽ V ⩽ 21.0), along with 33 night V + R light curves and astrometry for 109,866 stars (14.5 ⩽ V ⩽ 22.5).