WZ Sge-Type Dwarf Novae
WZ Sge-Type Dwarf Novae
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DOI：
10.1093/pasj/psv077
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发表时间：
2015-07
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影响因子：
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通讯作者：
Taichi Kato
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作者：
Taichi Kato
我们总结了目前对 WZ Sge 型矮新星的认识和最近获得的发现。我们还回顾了对这些天体认识的历史发展，提供了现代标准，并回顾了过去有关超级驼峰、早期超级驼峰和爆发机制的研究。我们认为早期超级驼峰（反映 2:1 共振）和长期或多次重亮的存在是 WZ Sge 型矮新星的最佳区别特征。我们主要根据 Kato 等人 VSNET 合作获得的数据，提供了近 100 颗 WZ Sge 型矮新星的更新列表。 （2015，arXiv/1507.05610）并讨论了统计数据。在所研究的WZ Sge型矮新星中，我们可以在63%中检测到振幅大于0.02星等的早期超级驼峰，这使得早期超级驼峰成为WZ Sge型矮新星的一个有用的区分特征。早期超级驼峰的理论光变曲线通常似乎再现了许多低振幅物体的存在，支持了早期超级驼峰的几何起源。利用最近开发的利用超级驼峰发展阶段（A阶段超级驼峰）测量质量比的方法，我们发现超级驼峰的周期变化与WZ Sge型天体的质量比之间存在线性关系。利用这种关系，我们可以绘制出大量WZ Sge型的演化图，并确定爆发类型为C型->D->A->B->E型的演化序列，其中B型天体存在一些异常值。超级驼峰 A 阶段（进化阶段）的持续时间也与估计的质量比密切相关。通过使用 A 阶段超级驼峰和 A 阶段硬质合金的质量比，我们已经能够确定周期弹跳器的最佳候选者。
We have summarized the current understanding and recently obtained findings about WZ Sge-type dwarf novae. We also reviewed the historical development of the understanding of these objects, provided the modern criteria, and reviewed the past research in relation to superhumps, early superhumps and the outburst mechanism. We regard that the presence of early superhumps (reflecting the 2:1 resonance) and long or multiple rebrightenings are the best distinguishing properties of WZ Sge-type dwarf novae. We provided the updated list of nearly 100 WZ Sge-type dwarf novae mainly based on the data obtained by the VSNET Collaboration up to Kato et al. (2015, arXiv/1507.05610) and discussed the statistics. We could detect early superhumps with amplitude larger than 0.02 mag in 63% of the studied WZ Sge-type dwarf novae, which makes early superhumps a useful distinguishing feature for WZ Sge-type dwarf novae. Theoretical light curves of early superhumps generally appear to reproduce the existence of many low-amplitude objects, supporting the geometrical origin of early superhumps. Using the recently developed method of measuring mass ratios using developing phase of superhumps (stage A superhumps), we showed that there is a linear relation between the period variation of superhumps and the mass ratio in WZ Sge-type objects. By using this relation, we were able to draw an evolutionary picture of a large number of WZ Sge-type and identified the type of outburst to be an evolutionary sequence: type C->D->A->B->E, with some outliers for type-B objects. The duration of stage A (evolutionary phase) of superhumps is also well correlated with the estimated mass ratios. By using mass ratios from stage A superhumps and durarion of stage A, we have been able to identify best candidates for period bouncers.