KIC 9406652 is a cataclysmic variable (CV), sub-classified as `IW And-type star', showing a repetition of standstills with oscillatory variations terminated by brightening. This system showed negative superhumps, semi-periodic variations having periods slightly shorter than the orbital period, and super-orbital signals, both of which are believed to originate from a precessing, tilted accretion disk. We have re-examined its Kepler light curve extending over 1500 d. In accordance with a cycle of the IW And-type light variation, the frequency of negative superhumps showed a reproducible variation: a rapid drop during the brightening and a gradual increase during the standstill. They are interpreted as the drastic change in the radial mass distribution and the expansion of the tilted disk, which is not expected from the existing models for IW And stars. The constancy in flux amplitudes of negative superhumps confirms that their light source is the bright spot sweeping across the surface of the tilted disk. The frequencies of negative superhumps and super-orbital signals varied in unison on long timescales, suggesting their common origin: the tilted disk. Orbital signals at the brightening were dominated by the irradiation of the secondary star and varied with the orientation of the tilted disk; the amplitude was maximized at the minimum of super-orbital signals and the light maximum shifted to early orbital phases as the super-orbital phase advances. This is the first direct evidence that the disk was tilted out of the binary orbital plane and retrogradely precessing. The tilt angle of the disk inferred from semi-amplitudes of super-orbital signals was lower than 3 degrees. The diversity in light curves of negative superhumps supports this and suggests that a part of the gas stream overflows the disk edge. This study thus offers rich information about the tilted disk in CVs.

中文翻译：

---

KIC 9406652：灾变变星倾斜圆盘实验室

KIC 9406652 是一个激变变星（CV），子分类为“IW 和型星”，显示了静止的重复，振荡变化因增亮而终止。该系统显示出负的超驼峰、周期略短于轨道周期的半周期变化以及超轨道信号，这两者都被认为来自进动的倾斜吸积盘。我们重新检查了其延伸超过 1500 天的开普勒光变曲线。根据 IW And 型光变化的周期，负超峰的频率呈现出可重复的变化：增亮时快速下降，静止时逐渐增加。它们被解释为径向质量分布的剧烈变化和倾斜盘的膨胀，这是 IW 和星星的现有模型所不期望的。负超峰通量幅度的恒定性证实了它们的光源是扫过倾斜圆盘表面的亮点。负超驼峰和超轨道信号的频率在很长的时间尺度上一致变化，表明它们的共同起源：倾斜的圆盘。增亮时的轨道信号以次星的辐照为主，并随倾斜盘的方向而变化；振幅在超轨道信号的最小值处最大化，随着超轨道相位的推进，光的最大值转移到早期轨道相位。这是该盘倾斜出双星轨道平面并逆行进动的第一个直接证据。从超轨道信号的半振幅推断出的圆盘倾角小于3度。负超峰的光变曲线的多样性支持了这一点，并表明部分气流溢出了圆盘边缘。因此，这项研究提供了关于 CV 中倾斜圆盘的丰富信息。