Eccentric ellipsoidal red giant binaries in the LMC: complete orbital solutions and comments on interaction at periastron
Eccentric ellipsoidal red giant binaries in the LMC: complete orbital solutions and comments on interaction at periastron
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DOI：
10.1111/j.1365-2966.2012.20492.x
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发表时间：
2012-01
影响因子：
4.8
通讯作者：
C. Nicholls;C. Nicholls;P. Wood
中科院分区：
文献类型：
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作者：
C. Nicholls;C. Nicholls;P. Wood
利用已知距离的椭球变星模型，即使在没有日食的情况下，也可以精确地确定两个组成部分的质量。我们提出这样的建模使用光和径向速度曲线的椭球红巨星双星在大麦哲伦星云（LMC），在那里他们也被称为序列E星。根据光变曲线的形状，恒星被选为可能的偏心系统。我们已经证实了他们的偏心性质，并获得了系统参数使用威尔逊Devinney代码。在我们的样本中，大多数恒星都表现出不等的光极大值和极小值，这是在具有圆形轨道的序列E变星中没有观察到的现象。我们发现证据表明，由于高偏心率和伴星的不同影响，红巨星的形状在整个轨道上发生变化。在其中两颗红巨星中可以明显看到短暂的脉动。我们确定脉动模式和评论他们的位置在周期光度平面。定义这些系统的参数铺平了道路的建模，以确定由什么机制偏心率保持在进化的二进制文件。
Modelling ellipsoidal variables with known distances can lead to exact determination of the masses of both components, even in the absence of eclipses. We present such modelling using light and radial velocity curves of ellipsoidal red giant binaries in the Large Magellanic Cloud (LMC), where they are also known as sequence E stars. Stars were selected as likely eccentric systems on the basis of light curve shape alone. We have confirmed their eccentric nature and obtained system parameters using the Wilson–Devinney code. Most stars in our sample exhibit unequal light maxima as well as minima, a phenomenon not observed in sequence E variables with circular orbits. We find evidence that the shape of the red giant changes throughout the orbit due to the high eccentricity and the varying influence of the companion. Brief intervals of pulsation are apparent in two of the red giants. We determine pulsation modes and comment on their placement in the period–luminosity plane. Defining the parameters of these systems paves the way for modelling to determine by what mechanism eccentricity is maintained in evolved binaries.