[论文解读] Orbital periods of cataclysmic variables identified by the SDSS. IX. NTT photometry of eight eclipsing and three magnetic systems

J. Southworth, C. Tappert+2 more|Keele Research Repository (Keele University)|Nov 10, 2014

Astrophysical Phenomena and Observations参考文献 59被引用 9

一句话总结

本研究利用NTT对11颗新发现的激变变星进行了测光观测，识别出八个食双星系统和三个磁性系统。报告了十个系统的首次轨道周期测量，包括四个新发现的食双星系统，其周期在89.8至197.2分钟之间，并通过塞曼效应发射特征确认了磁性变星的存在，结合食双星和磁性光变曲线分析，推进了对激变变星群体统计特征和物理性质的理解。

ABSTRACT

We report the discovery of eclipses and the first orbital period measurements for four cataclysmic variables, plus the first orbital period measurements for one known eclipsing and two magnetic systems. SDSS J093537.46+161950.8 exhibits 1-mag deep eclipses with a period of 92.245 min. SDSS J105754.25+275947.5 has short and deep eclipses and an orbital period of 90.44 min. Its light curve has no trace of a bright spot and its spectrum is dominated by the white dwarf component, suggesting a low mass accretion rate and a very low-mass and cool secondary star. CSS J132536+210037 shows 1-mag deep eclipses each separated by 89.821 min. SDSS J075653.11+085831.8 shows 2-mag deep eclipses on a period of 197.154 min. CSS J112634-100210 is an eclipsing dwarf nova identified in the Catalina Real Time Transit Survey, for which we measure a period of 111.523 min. SDSS J092122.84+203857.1 is a magnetic system with an orbital period of 84.240 min; its light curve is a textbook example of cyclotron beaming. A period of 158.72 min is found for the faint magnetic system SDSS J132411.57+032050.4, whose orbital light variations are reminiscent of AM Her. Improved orbital period measurements are also given for three known SDSS cataclysmic variables. We investigate the orbital period distribution and fraction of eclipsing systems within the SDSS sample and for all cataclysmic variables with a known orbital period, with the finding that the fraction of known CVs which are eclipsing is not strongly dependent on the orbital period.

研究动机与目标

• 测量来自SDSS巡天的新发现激变变星的精确轨道周期。
• 识别并表征食双星系统，以实现对激变变星组分的高精度质量和半径测量。
• 研究激变变星群体中轨道周期分布与食双星比例的关系，特别是与周期间隙的关系。
• 通过显示塞曼效应发射特征的测光光变曲线，确认并表征磁性激变变星。

提出的方法

• 利用NTT/EFOSC2仪器进行时间序列测光，监测11颗激变变星的光变行为。
• 通过拟合光变曲线并识别光深度的周期性凹陷，推导出食深度和轨道周期。
• 通过光谱分析并与已知激变变星模板比较，确认了磁性及吸积系统的分类。
• 基于RKCat和文献数据，构建了SDSS激变变星及食双星子集的轨道周期分布。
• 在磁性系统的光变曲线中识别出塞曼效应发射特征，特别是在SDSS J0921和SDSS J1324中，其特征与AM Her型系统相似。
• 通过统计分析比较不同轨道周期下食双星的比例，评估RKCat星表的完备性。

实验结果

研究问题

• RQ1 从SDSS样本中新发现的八个食双星激变变星的轨道周期是什么？
• RQ2 像SDSS J0921和SDSS J1324这样的磁性激变变星的光变曲线与已知的塞曼辐射型系统（如AM Her）相比有何异同？
• RQ3 食双星的比例是否依赖于轨道周期，特别是在周期间隙区域？
• RQ4 从低质量、低吸积率系统（如SDSS J1057）的食双星光变曲线中可以推断出哪些物理特性？
• RQ5 为何在较长轨道周期下食双星的比例更高？这与星表不完备性有何关联？

主要发现

• SDSS J093537.46+161950.8的轨道周期为92.245 ± 0.008分钟，食深度达1等。
• SDSS J105754.25+275947.5的轨道周期为90.44 ± 0.06分钟，表现出短而深的食，且无亮斑特征。
• CSS J132536+210037表现出1等深度的食，周期为89.821 ± 0.009分钟，这是该系统的首次周期测量。
• SDSS J075653.11+085831.8表现出2等深度的食，周期为197.154 ± 0.025分钟，证实其为食双星。
• 磁性系统SDSS J092122.84+203857.1的轨道周期为84.240 ± 0.004分钟，其光变曲线显示出塞曼辐射特征。
• 较暗的磁性系统SDSS J132411.57+032050.4的轨道周期为158.72 ± 0.10分钟，光变特征与AM Her型系统相似。