FIRST MODERN PHOTOMETRIC INVESTIGATION OF THE PUZZLING W UMa TYPE CLOSE BINARY SYSTEM OF TZ BOOTIS
FIRST MODERN PHOTOMETRIC INVESTIGATION OF THE PUZZLING W UMa TYPE CLOSE BINARY SYSTEM OF TZ BOOTIS
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DOI：
10.1088/0004-6256/142/4/99
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
P. Christopoulou;A. Parageorgiou;I. Chrysopoulos
中科院分区：
文献类型：
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作者：
P. Christopoulou;A. Parageorgiou;I. Chrysopoulos
本文介绍了2010年对一颗令人困惑的WUma型星星TZ Bootis的CCD测光BVRI观测结果。通过使用更新版本的Wilson-Devinney代码，第一个现代光度解决方案推导出新的光度观测和已公布的光谱数据。这个低质量比的双星是一个深接触系统，f = 52%的A-亚型。采用光斑模型来拟合光变曲线的特殊特征。根据我们的七个新的光极小时和70年来文献中收集的所有其他光极小时，我们从O-C曲线研究了轨道周期。发现存在一个31.2年的周期变化，振幅为0.033天，覆盖了一个以dP/dt = −2.1 × 10−8天/年的速率下降的长期变化。循环周期的变化可能表明，TZ Boo是一个三重或四重系统，从公布的光谱数据证实。长期的轨道周期减小是由于质量较大的组分向质量较小的组分的质量转移和/或由于磁破碎引起的角动量损失，这将导致过接触程度增加，最终双星将演化为单个快速旋转的星星。
New CCD photometric BVRI observations of the puzzling W UMa type binary star, TZ Bootis, are presented from our observations in 2010. By using the updated version of the Wilson–Devinney code, the first modern photometric solution is deduced from new photometric observations and published spectroscopic data. This low mass ratio binary turns out to be a deep overcontact system with f = 52% of A-subtype. A spot model has been applied to fit the particular features of light curves. Based on our seven new light minimum times and all others compiled from the literature over 70 yr, we studied the orbital period from the O–C curve. It is found that a 31.2 yr cyclic variation exists with an amplitude of 0.033 days, overlaying a secular decrease at a rate of dP/dt = −2.1 × 10−8 days yr−1. The cyclic period change may indicate that TZ Boo is a triple or a quadruple system as confirmed from the published spectroscopic data. The long-term orbital period decrease is interpreted by mass transfer from the more to the less massive component and/or angular momentum loss by the magnetic breaking which would cause the overcontact degree to increase and finally the binary will evolve into a single rapidly rotating star.