The (O–C) diagram problem of triple pre-cataclysmic system V471 Tau solved
The (O–C) diagram problem of triple pre-cataclysmic system V471 Tau solved
复制标题
三重预催化系统 V471 Tau 的 (O–C) 图问题已解决
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
L. Hric
中科院分区：
文献类型：
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作者：
E. Kundra;L. Hric
V471 Tau是由威尔逊发现的光谱双星（恒星径向速度总目录，第44页，1953）。它是后公共包络系统的原型，也是灾难性双星的前身。该系统由一颗冷红矮星K2 V（很可能是一颗主序星）和一颗热白矮星组成。该天体被归类为一个轨道周期约为0.5天的紧密双星。此外，在光曲线上观测到191天周期的光变化，这与红矮星的椭球形状以及这一冷组分表面斑点的迁移有关。双星中的白矮星的月食持续49分钟，然后下降到最小值，从最小值上升到最小值只需要55秒。这样的光度行为阻碍了获得良好的日食。在本文中，我们以高时间分辨率在四年中获得了七次日食，所有四次接触都达到了精确的最小时间。幸运的是，这些极小值的时间在（O-C）图中显示出趋势的变化，我们能够确定导致（O-C）图行为的物理过程。我们证明了这种行为是由系统中轨道周期为33.2年的第三个天体引起的，并给出了它的物理和几何参数。对于倾角大于35°的天体，我们得到的质量低于稳定的氢燃烧极限，因此最有可能的候选者将是一颗褐矮星。
V471 Tau was discovered as a spectroscopic binary by Wilson (General Catalogue of Stellar Radial Velocities, p. 44, 1953). It is the prototype of a post-common envelope system and a progenitor of a cataclysmic binary. The system consists of a cool red dwarf, K2 V, very probably a main sequence star and a hot white dwarf. The object was classified as a close binary with an orbital period of around 0.5 days. Moreover, on the light curve are observed light variations with a period of 191 days, which are connected with an ellipsoidal shape of the red dwarf as well as with the migration of spots on the surface of this cool component. The eclipse of the white dwarf in the binary remains 49 minutes and declines to the minimum and the increase from the minimum takes only 55 s. Such photometric behaviour hinders obtaining good eclipses. In this paper we have obtained during four years seven eclipses with high time resolution with all four contacts to reach precise times of minima. Fortunately these times of the minima show a change of trend in the (O–C) diagram, and we were able to decide about the physical processes responsible for the behaviour of the (O–C) diagram. We showed that this behaviour is caused by a third body in the system with an orbital period of 33.2 years, and its physical and geometrical parameters are presented. For an inclination larger than 35° we get the mass of this body below the stable hydrogen-burning limit and thus most probably the candidate would be a brown dwarf.