PHOTOMETRY OF VARIABLE STARS FROM THE THU-NAOC TRANSIENT SURVEY. I. THE FIRST TWO YEARS
PHOTOMETRY OF VARIABLE STARS FROM THE THU-NAOC TRANSIENT SURVEY. I. THE FIRST TWO YEARS
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DOI：
10.1088/0004-6256/150/4/107
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发表时间：
2015-07
期刊：
影响因子：
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通讯作者：
X. Yao;Lingzhi Wang;Xiaofeng Wang;Tianmeng Zhang;Juncheng Chen;W. Yuan;J. Mo;Wenxiong Li;Z. Jin;Xue-Bing Wu;J. Nie;Xu Zhou
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作者：
X. Yao;Lingzhi Wang;Xiaofeng Wang;Tianmeng Zhang;Juncheng Chen;W. Yuan;J. Mo;Wenxiong Li;Z. Jin;Xue-Bing Wu;J. Nie;Xu Zhou
本文报道了清华大学-中国国家天文台瞬变巡天对1300平方度天区的观测结果。总共探测到1237颗变星（包括299颗新的变星），亮度<18.0等，星等变化<0.1等，时间尺度从几小时到几百天。在这些观测中，我们初步鉴定了661颗天琴座RR星，431颗双星，72颗半规则变星，29颗米拉星，11颗慢不规则变星，11颗RS犬座星，7颗剑鱼座Gamma星，5颗长周期变星，3颗室女座W星，3颗盾牌座Delta星，2颗异常造父变星，1颗造父变星，和1颗类新星星星。此外，我们还发现14颗天琴座RR型星表现出Blazhko效应，67颗接触食双星表现出O 'Connell效应。由于天琴座RR型变星的光变周期和振幅取决于其化学成分，因此它们的光度观测可以用来研究金属丰度沿着垂直于银盘方向的分布。我们发现，RR型天琴座恒星的金属丰度在靠近银河平面的区域表现出较大的分散性（例如，−3.0 < [Fe/H] < 0），但在银河系纬度较大的地区趋于收敛于[Fe/H]<$−1.7。这种变化可能与银河晕中的RRAB天琴座恒星来自不同金属丰度和垂直距离的球状星团有关，即，OoI和OoII种群，支持双晕模型。
In this paper, we report the detections of stellar variabilities from the first two years of observations of a sky area of about 1300 square degrees from the Tsinghua University–NAOC Transient Survey. A total of 1237 variable stars (including 299 new ones) were detected with a brightness <18.0 mag and a magnitude variation ≳0.1 mag on a timescale from a few hours to a few hundred days. Among such detections, we tentatively identified 661 RR Lyrae stars, 431 binaries, 72 semi-regular pulsators, 29 Mira stars, 11 slow irregular variables, 11 RS Canum Venaticorum stars, 7 Gamma Doradus stars, 5 long-period variables, 3 W Virginis stars, 3 Delta Scuti stars, 2 Anomalous Cepheids, 1 Cepheid, and 1 nova-like star based on their time-series variability index Js and their phased diagrams. Moreover, we found that 14 RR Lyrae stars show the Blazhko effect and 67 contact eclipsing binaries exhibit the O’Connell effect. Since the period and amplitude of light variations of RR Lyrae variables depend on their chemical compositions, their photometric observations can be used to investigate the distribution of metallicity along the direction perpendicular to the Galactic disk. We find that the metallicity of RR Lyrae stars shows large scatter at regions closer to the Galactic plane (e.g., −3.0 < [Fe/H] < 0) but tends to converge at [Fe/H] ∼ −1.7 at larger Galactic latitudes. This variation may be related to the fact that the RRAB Lyrae stars in the Galactic halo come from globular clusters with different metallicities and vertical distances, i.e., OoI and OoII populations, favoring the dual-halo model.