IW And-type state in IM Eridani
IW And-type state in IM Eridani
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IM Eridani 中的 IW And 型状态
DOI：
10.1093/pasj/psz130
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发表时间：
2019
影响因子：
2.3
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
Kato Taichi、Wakamatsu Yasuyuki、Kojiguchi Naoto、Kimura Mariko;et al.
w：恒星是最近才被发现的一组矮新星，它们的特征是从静止的阶段开始不断变亮，伴随着衰减振荡，然后是深度下降。Kimura等人（2019，PASJ，提交）最近提出了一种基于倾斜盘中热粘性盘不稳定性的模型，以再现IW和型特征。imeri在2018年经历了IW和型阶段，我们记录了三个周期（阻尼）振荡阶段，以增亮结束。我们确定了IW和型状态的两个周期：4-5天的小幅度（通常是阻尼）振荡和34-43天的长周期。这种行为是典型的IW和型恒星。在下一次增亮之前的长周期内，物体逐渐变亮，这终止了（阻尼）振荡阶段。这一观测结果与Kimura等人在倾斜圆盘中热粘性圆盘不稳定性模型所预测的在长周期内圆盘质量增加的结果一致。然而，我们没有成功地探测到负超级峰，这被认为是倾斜圆盘的特征。
IW And stars are a recently recognized group of dwarf novae which are characterized by a repeated sequence of brightening from a standstill-like phase with damping oscillations followed by a deep dip. Kimura et al. (2019, PASJ, submitted) recently proposed a model based on thermal-viscous disk instability in a tilted disk to reproduce the IW And-type characteristics. IM Eri experienced the IW And-type phase in 2018 and we recorded three cycles of the (damping) oscillation phase terminated by brightening. We identified two periods during the IW And-type state: 4–5 d small-amplitude (often damping) oscillations and a 34–43 d long cycle. This behavior is typical for an IW And-type star. The object gradually brightened within the long cycle before the next brightening, which terminated the (damping) oscillation phase. This observation agrees with the increasing disk mass during the long cycle predicted by the Kimura et al. model of thermal-viscous disk instability in a tilted disk. We did not, however, succeed in detecting negative superhumps, which are considered to be the signature of a tilted disk.