On the effects of rotation on acoustic stellar pulsations: validity domains of perturbative methods and close frequency pairs Effects of rotation on acoustic pulsations
On the effects of rotation on acoustic stellar pulsations: validity domains of perturbative methods and close frequency pairs Effects of rotation on acoustic pulsations
复制标题
关于旋转对声学恒星脉动的影响：微扰方法和相近频率对的有效域 旋转对声学脉动的影响
DOI：
10.1111/j.1365-2966.2011.18453.x
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发表时间：
2011
影响因子：
4.8
通讯作者：
Burke K
中科院分区：
文献类型：
--
作者：
Burke K
用微扰方法和二维方法计算了实际旋转恒星模型的声学模式的脉动频率。两者之间的比较产生了与Reese等人先前获得的类似的有效域。用于多变模型。我们还可以基于对二维方法的频率的多项式拟合来构造有效域，并且这些域也被证明是相似的，从而进一步证实了微扰方法和二维方法在低转速下的一致性。此外，正如先前在埃斯皮诺萨等人中所示，多重态中的相邻频率接近在一起，从而形成对。这一现象被证明不太可能解释在δScuti恒星中观察到的近频率对，这是二维计算所独有的。还对计算的频谱中所有接近的频率对进行了系统的搜索。近距离频率对的数量与基于泊松分布的预期一致，但与FG Vir等恒星中近距离频率对的数量或分布不匹配。此外，在频率倍增不重叠的低转速下，出现了缺乏接近的频率对。目前被报道具有接近频率对的δScuti恒星不会在这段时间内坠落。
Pulsation frequencies of acoustic modes are calculated for realistic rotating stellar models using both a perturbative and a two-dimensional approach. A comparison between the two yields validity domains which are similar to those previously obtained in Reese et al. for polytropic models. One can also construct validity domains based on polynomial fits to the frequencies from the two-dimensional approach, and these also turn out to be similar, thus further confirming the agreement between the perturbative and the two-dimensional approaches at low rotation rates. Furthermore, as was previously shown in Espinosa et al., adjacent frequencies in multiplets come close together, thus forming pairs. This phenomenon, exclusive to two-dimensional calculations, is shown to be an unlikely explanation of the close frequency pairs observed in δ Scuti stars. A systematic search for all close frequency pairs in the calculated spectrum is also carried out. The number of close frequency pairs is shown to agree with what is expected based on a Poisson distribution, but does not match the number or distribution of close pairs in stars such as FG Vir. Furthermore, a lack of close frequency pairs appears at low rotation rates, where frequency multiplets do not overlap. δ Scuti stars currently reported as having close frequency pairs do not fall in this interval.