Detecting non-uniform period spacings in the Kepler photometry of γ Doradus stars: methodology and case studies
Detecting non-uniform period spacings in the Kepler photometry of γ Doradus stars: methodology and case studies
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DOI：
10.1051/0004-6361/201424585
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发表时间：
2014-10
影响因子：
6.5
通讯作者：
T. V. Reeth;A. Tkachenko;C. Aerts;P. Pápics;P. Degroote;J. Debosscher;K. Zwintz;S. Bloemen;
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文献类型：
--
作者：
T. V. Reeth;A. Tkachenko;C. Aerts;P. Pápics;P. Degroote;J. Debosscher;K. Zwintz;S. Bloemen;
上下文。对恒星振荡的分析是探测恒星内部最可靠的方法之一。最近的太空任务，如开普勒，为我们提供了一个以前所未有的细节研究这些振荡的机会。对于许多多周期的脉动星，例如剑鱼座的恒星，这导致探测到几十到数百个从地面观测中找不到的振荡频率。目标。我们的目标是探测开普勒观测到的剑鱼座恒星样本的傅里叶光谱中的非均匀周期间隔。这种探测由于空间测光中的大量有效频率和重叠不等距的旋转分裂的多重波而变得复杂。方法：研究方法。根据剑鱼星引力模式振荡的理论性质，我们发展了一种周期间隔探测方法，并将其应用于开普勒对几颗恒星的观测，通过模拟验证了该方法的性能。结果。这项技术的应用使5个处理过的开普勒目标中的3个清楚地检测到了非均匀周期间隔序列。文中还讨论了该技术的缺点，包括不能在不增加理论模型的情况下区分振荡模式的球度和方位阶的不同值。结论。尽管有这些缺点，但该方法被证明可以可靠地探测到剑鱼座恒星的周期间隔，这将使未来对这些恒星的星震分析成为可能。
Context. The analysis of stellar oscillations is one of the most reliable ways to probe stellar interiors. Recent space missions such as Kepler have provided us with an opportunity to study these oscillations with unprecedented detail. For many multi-periodic pulsators such as {\gamma} Doradus stars, this led to the detection of dozens to hundreds of oscillation frequencies that could not be found from ground-based observations. Aims. We aim to detect non-uniform period spacings in the Fourier spectra of a sample of {\gamma} Doradus stars observed by Kepler. Such detection is complicated by both the large number of significant frequencies in the space photometry and by overlapping non-equidistant rotationally split multiplets. Methods. Guided by theoretical properties of gravity-mode oscillation of {\gamma} Doradus stars, we developed a period-spacing detection method and applied it to Kepler observations of a few stars, after having tested the performance from simulations. Results. The application of the technique resulted in the clear detection of non-uniform period spacing series for three out of the five treated Kepler targets. Disadvantages of the technique are also discussed, and include the disability to distinguish between different values of the spherical degree and azimuthal order of the oscillation modes without additional theoretical modelling. Conclusions. Despite the shortcomings, the method is shown to allow solid detections of period spacings for {\gamma} Doradus stars, which will allow future asteroseismic analyses of these stars.