The most plausible explanation of the cyclic period changes in close binaries: the case of the RS CVn-type binary WW Dra
The most plausible explanation of the cyclic period changes in close binaries: the case of the RS CVn-type binary WW Dra
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对邻近双星循环周期变化最合理的解释：RS CVn 型双星 WW Dra 的情况
DOI：
10.1111/j.1365-2966.2010.16584.x
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发表时间：
2010-04
影响因子：
4.8
通讯作者：
Qian, S. -B.
中科院分区：
文献类型：
--
作者：
Liao, W. -P.;Qian, S. -B.
在紧密的双星系统中，周期变化是一个相当普遍的现象，通常被解释为由一个或两个组成部分的磁活动或第三个物体的光旅行时间效应（LTTE）引起的。我们检索了已知质量比和次级成分光谱类型的182个ea型（包括Hall使用的101个Algol系统）、43个eb型和53个ew型双星的轨道周期变化。根据新收集的数据，我们在Hall中对图表进行了复制和改进。我们的图不支持Hall得出的结论，即循环周期的变化仅限于具有光谱类型晚于F5的次级分量的双星。在具有早期次级成分的系统中，周期变化的存在表明，磁活动是周期变化的一个原因，但不是唯一的原因。我们发现，可能由于存在第三个天体而导致的循环周期变化，在紧密系统中的ew型双星中更为频繁。因此，对循环周期变化最合理的解释是LTTE通过第三体的存在。利用百年来光极小期的历史记录，分析了大人马座双星wwdra的旋回周期变化。发现双星的轨道周期表现出类似于112.2年的周期变化，振幅类似于0.1977 d。这种周期振荡可以通过质量不小于6.43M（圆点）的第三个天体归因于LTTE。然而，没有发现第三个天体的光谱线，这表明它可能是一个候选黑洞。第三个天体的轨道距离比14.4天文单位更近，可能在这个系统的演化中发挥重要作用。
Cyclic period changes are a fairly common phenomenon in close binary systems and are usually explained as being caused either by the magnetic activity of one or both components or by the light travel time effect (LTTE) of a third body. We searched the orbital period changes in 182 EA-type (including the 101 Algol systems used by Hall), 43 EB-type and 53 EW-type binaries with known mass ratio and spectral type of the secondary component. We reproduced and improved the diagram in Hall according to the new collected data. Our plots do not support the conclusion derived by Hall that cyclic period changes are restricted to binaries having a secondary component with spectral type later than F5. The presence of period changes among systems with a secondary component of early type indicates that magnetic activity is one, but not the only, cause of the period variation. It is discovered that cyclic period changes, probably resulting from the presence of a third body, are more frequent in EW-type binaries among close systems. Therefore, the most plausible explanation of the cyclic period changes is the LTTE through the presence of a third body. Using the century-long historical record of the times of light minimum, we analysed the cyclic period change in the Algol binary WW Dra. It is found that the orbital period of the binary shows a similar to 112.2-yr cyclic variation with an amplitude of similar to 0.1977 d. The cyclic oscillation can be attributed to the LTTE by means of a third body with a mass no less than 6.43M(circle dot). However, no spectral lines of the third body were discovered, indicating that it may be a candidate black hole. The third body is orbiting the binary at a distance closer than 14.4 au and may play an important role in the evolution of this system.
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影响因子：
6.5
作者：
Ö. Çakırlı;C. Ibanoğlu;G. Djurašević;S. Erkapić;S. Evren;G. Tas
通讯作者：
Ö. Çakırlı;C. Ibanoğlu;G. Djurašević;S. Erkapić;S. Evren;G. Tas
类新星灾难变星 AC Cancri 的轨道周期变化：磁制动的证据和看不见的伴星
影响因子：
6.5
作者：
通讯作者：
--
DOI：
10.1086/307185
发表时间：
1999-05
期刊：
The Astrophysical Journal
影响因子：
--
作者：
G. Rauw;J. Vreux;B. Bohannan
通讯作者：
G. Rauw;J. Vreux;B. Bohannan
影响因子：
6.5
作者：
P. Mayer;R. Lorenz;H. Drechsel;A. Abseim
通讯作者：
P. Mayer;R. Lorenz;H. Drechsel;A. Abseim
DOI：
10.1111/j.1365-2966.2005.09963.x
发表时间：
2006-03
影响因子：
4.8
作者：
Li-ying Zhu;S. Qian
通讯作者：
Li-ying Zhu;S. Qian