Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion
Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion
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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
DOI：
10.1051/0004-6361:20065970
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发表时间：
2007-05
影响因子：
6.5
通讯作者：
中科院分区：
文献类型：
--
作者：
目标。源AC Cnc是一个类新星激变变星，包含一个质量为0.76 M圆点的白矮星主星和一个质量为0.77 M圆点的K2型主星。我们打算研究它的周期变化，并寻找磁制动和看不见的第三个身体的证据。方法.通过对一个新的日食时刻与文献中的其他日食时刻组合而成的O-C曲线的分析，研究了O-C曲线的周期变化。结果一个周期为16.2年的周期变化被发现是叠加在一个长期的周期减少率。P = -1.24（+/- 0.44）x 10（-8）天/年。结论.结果表明，磁活动驱动次级星星四极动量变化的机制（阿普尔盖特机制）并不容易解释。这种周期振荡可以用光旅行时间效应来解释，这种效应是由一个冷的M-型矮伴星（M-3 > 0.097 M圆点）在长轨道（16.2年）上围绕双星所引起的。由于两个组分的质量几乎相同，从叶填充次级到初级的质量传递是无效的，从而导致连续周期减小。这可能是来自K2型成分的增强的磁性恒星风的有力证据。如果冷次级的阿尔芬半径与太阳的阿尔芬半径相同（即，R-A = 15 R-圆点），质量损失率应为。M-2 = -1.65 x 10（-10）M圈点/年。通过使用Tout和Eggleton（1988）提出的增强质量损失，质量损失率应为。M-2 = -1.18 x 10（-9）M圈点/年。在这种情况下，阿尔芬半径被确定为R-A = 5.2 R圆点。然而，周期的长期减小可能只是由附加天体的存在引起的长周期（> 100年）振荡的一部分。为了检验结论，需要新的精确的光最小时间。
Aims. The source AC Cnc is a nova-like cataclysmic variable containing a white-dwarf primary with a mass of 0.76 M-circle dot and a K2-type secondary with a mass of 0.77 M-circle dot. We intend to study its period changes and search for evidence of magnetic braking and unseen third body. Methods. The period changes were investigated based on the analysis of the O-C curve, which is formed by one new eclipse time together with the others compiled from the literature. Results. A cyclic change with a period of 16.2 yr was found to be superimposed on a long-term period decrease at a rate of. P = -1.24(+/- 0.44) x 10(-8) days/year. Conclusions. It is shown that the mechanism of magnetic activity-driven changes in the quadrupole momentum of the secondary star (Applegate's mechanism) does not explain it easily. This period oscillation was plausibly interpreted by a light-travel time effect caused by the presence of a cool M-type dwarf companion (M-3 > 0.097 M-circle dot) in a long orbit (16.2 yr) around the binary. Since the masses of both components are nearly the same, the mass transfer from the lobe-filling secondary to the primary is not efficient to cause the continuous period decrease. It may be strong evidence of an enhanced magnetic stellar wind from the K2-type component. If the Alfen radius of the cool secondary is the same as that of the Sun (i.e., R-A = 15 R-circle dot), the mass-loss rate should be. M-2 = -1.65 x 10(-10) M-circle dot/year. By using the enhanced mass loss proposed by Tout & Eggleton (1988), the mass-loss rate should be. M-2 = -1.18 x 10(-9) M-circle dot/year. In this case, the Alfen radius is determined to be R-A = 5.2 R-circle dot. However, the long-term decrease of the period may be only a part of a long-period (> 100 yr) oscillation caused by the presence of an additional body. To check the conclusions, new precise times of light minimum will be required.
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影响因子：
--
作者：
B. Warner
通讯作者：
B. Warner
DOI：
10.1086/161990
发表时间：
1984-05
期刊：
The Astrophysical Journal
影响因子：
--
作者：
E. Schlegel;R. Kaitchuck;R. Honeycutt
通讯作者：
E. Schlegel;R. Kaitchuck;R. Honeycutt
影响因子：
3.5
作者：
A. Okazaki;M. Kitamura;A. Yamasaki
通讯作者：
A. Okazaki;M. Kitamura;A. Yamasaki
DOI：
10.1046/j.1365-8711.1998.01446.x
发表时间：
1998-06
影响因子：
4.8
作者：
Antonino Francesco Lanza;M. Rodonò;R. Rosner
通讯作者：
Antonino Francesco Lanza;M. Rodonò;R. Rosner
影响因子：
4.8
作者：
C. Tout;D. Hall
通讯作者：
C. Tout;D. Hall