Photometric amplitudes and phases of nonradial oscillation in rotating stars
Photometric amplitudes and phases of nonradial oscillation in rotating stars
复制标题
旋转恒星非径向振荡的光度振幅和相位
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
M. Goupil
中科院分区：
文献类型：
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作者：
J. Daszyńska;W. Dziembowski;A. Pamyatnykh;M. Goupil
研究了旋转模式耦合对恒星振荡光度参数的影响。在中等旋转速率下，如果频率接近，则球谐度$ell$（相差2）和相同方位角阶m的模式之间会发生强耦合。这是在主序脉动中常见的情况。本文报道了一系列双模和三模耦合的β -造父变星模型的数值结果。模式耦合的一个后果是在光度模式识别中应考虑更高程度的模式。具有标称度$ellle2$的模态获得大量的$ellle2$分量，因此更有可能达到可检测的振幅。基于多色光度法的振幅比-相位差图中的耦合模式位置既依赖于纵横向又依赖于m。给出了变向图中模态路径的实例。星图仍然是识别旋转恒星模式的有用工具，但必须谨慎使用。
Effects of rotational mode coupling on photometric parameters of stellar oscillations are studied. At moderate rotation rates, a strong coupling between modes of spherical harmonic degree, $ell$, differing by 2 and of the same azimuthal order, m , takes place if the frequencies are close. This is a common situation amongst main sequence pulsators. Numerical results for a sequence of β Cephei star models are reported for the two- and three-mode couplings. One consequence of mode coupling is that modes of higher degree should be considered in photometric mode identification. Modes with nominal degree $ell>2$ acquire substantial $ellle2$ components and therefore are more likely to reach detectable amplitudes. Coupled mode positions in the amplitude ratio – phase difference diagrams, based on multicolour photometry, become both aspect- and m -dependent. Examples of the mode path in the diagram with varying aspect are given. The diagrams remain a useful tool for mode identification in rotating stars but the tool must be used with care.