Exoplanets in the Antarctic Sky. IV. Dual-band Photometry of Variables Found by the CSTAR-II Commissioning Survey at the North Sky
Wittenmyer, Robert A.; Wang, Lifan; Yang, Ming; Suntzeff, Nicholas B.; Wang, Songhu; Wang, Xiaofeng; Hu, Lei; Zhou, Hongyan; Jiang, Peng; Wright, Duncan; Zhang, Hui; Wei, Peng; Tao, Charling; Liu, Huigen; Sun, Tianrui; Li, Xiaoyan; Li, Zhengyang; Du, Fujia; Yang, Shihai; Gu, Bozhong; Yuan, Xiangyan; Zhu, Zhenxi; Yu, Zhouyi; Cui, Xiangqun; Gong, Xuefei; Mould, Jeremy; Tian, Qiguo; Uddin, Syed A.; Xu, Lingzhe; Zhou, Ji-lin; Liang, En-Si; Zhu, Jiapeng; Lu, Hongke
China, Australia, United States, France
Abstract
From the experiences learned in three decades of exoplanet search, wide-field transit surveys have proven to be one of the most effective ways to detect exoplanets. Wide field of view, however, suffers from high false-positive rates caused by blended eclipsing binaries. The chromaticity in eclipse depth is an effective feature to distinguish low-depth eclipsing binaries from transiting exoplanets, making multiple-band photometry follow-up advantageous before a target is passed onto more expensive spectroscopic follow-up. Moreover, a multiple-band photometric survey is itself a powerful method to find and vet planetary candidates and narrow down the candidate list of high-priority targets. In this work, we report the first results of a dual-band (Sloan-g and -i) wide-field photometry survey -- the Chinese Small Telescope ARray II (CSTAR-II), an updated version of the original CSTAR. As a key component of the Chinese Exoplanet Searching Program from Antarctica, CSTAR-II has been tested thoroughly at a remote arctic site near Mohe during the winter of 2014. In total, 13,531 light curves with the best overall photometric precision of ∼3 mmag were extracted from 7721 stars in the Sloan-g and -i bands. Using a robust method, we have detected 63 variables, of which 48 are newly discovered. The dual-band photometric results as well as the stellar properties of the detected sources are provided in this work.