Automated determination of g-mode period spacing of red giant stars
Automated determination of g-mode period spacing of red giant stars
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DOI：
10.1093/mnras/stu2499
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发表时间：
2014-12
影响因子：
4.8
通讯作者：
A. Datta;A. Mazumdar;Umang Gupta;S. Hekker
中科院分区：
文献类型：
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作者：
A. Datta;A. Mazumdar;Umang Gupta;S. Hekker
开普勒卫星提供了空前长度、占空比和精确度的测光时间序列数据。为了全面分析开普勒观测到的数万颗恒星的数据，自动化方法是先决条件。在这里，我们提出了一个自动化的程序来确定红巨星的重力模式的周期间隔上升的红巨星分支。重力模式存在于恒星内部深处的空腔中，并提供有关恒星核心条件的信息。然而，对于红巨星，引力模在表面上不能直接观测到，因此这种方法是基于压力-引力混合模，这些模在傅立叶功率谱中呈现出可观测的特征。这里提出的方法是基于这些混合模式的垂直对齐和对称性的周期阶梯图。我们发现，我们可以得到可靠的结果模型频率和观测频率。此外，我们进行了蒙特卡罗测试，以获得现实的不确定性的周期间隔与不同的振荡模式（模型）和频率的不确定性。此外，该方法已被用来改善模式检测和识别的观察到的频率在一个迭代的方式。
The Kepler satellite has provided photometric timeseries data of unprecedented length, duty cycle and precision. To fully analyse these data for the tens of thousands of stars observed by Kepler, automated methods are a prerequisite. Here we present an automated procedure to determine the period spacing of gravity modes in red-giant stars ascending the red-giant branch. The gravity modes reside in a cavity in the deep interior of the stars and provide information on the conditions in the stellar core. However, for red giants the gravity modes are not directly observable on the surface, hence this method is based on the pressure-gravity mixed modes that present observable features in the Fourier power spectrum. The method presented here is based on the vertical alignment and symmetry of these mixed modes in a period echelle diagram. We find that we can obtain reliable results for both model frequencies and observed frequencies. Additionally, we carried out Monte Carlo tests to obtain realistic uncertainties on the period spacings with different set of oscillation modes (for the models) and uncertainties on the frequencies. Furthermore, this method has been used to improve mode detection and identification of the observed frequencies in an iterative manner.