KIC 7284688: A Solar-type Eclipsing Binary with Rapidly Varying O’Connell Effect
KIC 7284688: A Solar-type Eclipsing Binary with Rapidly Varying O’Connell Effect
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DOI：
10.3847/1538-3881/accfa1
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发表时间：
2023-05
期刊：
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通讯作者：
Yang Pan;Xiaobin Zhang
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作者：
Yang Pan;Xiaobin Zhang
我们基于开普勒、TESS和LAMOST数据，对短周期食双星KIC-7284688进行了全面的光度和光谱研究。径向速度分析表明，它是由一颗质量接近相等的双星加上一颗视线恒星组成的三线系统。双星中各组分的质量和半径分别为M1=1.142±0.020M⊙，R1=1.204±0.051R⊙，M2=1.119±0.019M⊙，R2=1.149±0.052R⊙。除了日食外，双星的光曲线还表现出快速变化的O‘Connell效应，即光极大值不等，这可以归因于恒星黑子的不同步旋转。我们分析了光残差数据的变异性、光极大值(MaxI.−Max.II)和光极小历元之间的差异，确定了0.644天的旋转周期。此外，我们还从(MaxI.∼Max.II)和极小的光时间数据中探测到了−为213d的准周期，这与自转周期(∼0.644天)和轨道周期(∼0.646天)之间的节拍几乎相同。我们的结论是，系统上O‘Connell的准周期变化可能与恒星黑子的迁移有关，与时间尺度从几年到几十年的磁周期相比，这是一个非常快的变化。
We present comprehensive photometric and spectroscopic study of the short-period eclipsing binary KIC 7284688 based on the Kepler, TESS, and LAMOST data. The radial-velocity analysis indicates that it is a triple-lined system composed of a nearly equal-mass binary plus a line-of-sight star. The masses and radii of the components in the binary are measured to be M 1 = 1.142 ± 0.020M ⊙, R 1 = 1.204 ± 0.051R ⊙, and M 2 = 1.119 ± 0.019M ⊙, R 2 = 1.149 ± 0.052R ⊙. In addition to the eclipses, the light curves of the binary exhibit exhibit rapidly changing O’Connell effect, namely the inequality in light maxima, which could be attributed to the asynchronous rotation of the starspots. We analyzed the variability in the data of light residuals, the difference between light maxima (Max.I−Max.II) as well as the epochs of light minima and determined a rotation period of 0.644 days. Moreover, we detected a quasiperiod with ∼213 days from both the data of (Max.I−Max.II) and light times of minima, which is almost identical to the beat between the rotation period (∼0.644 days) and the orbital period (∼0.646 days). We conclude that the quasiperiodic variations of the O’Connell on the system are probably related to the starspot migration and this is a very rapid variation compared to the magnetic cycles with timescales ranging from years to decades.