论文标题
上主序列中内重力波的光度检测。 iii。使用Celerite2的比较振幅光谱拟合和高斯过程回归
Photometric detection of internal gravity waves in upper main-sequence stars. III. Comparison of amplitude spectrum fitting and Gaussian process regression using celerite2
论文作者
论文摘要
使用空间光度法对大型恒星的研究表明，它们通常表现出随机的低频（SLF）变异性。这被解释为是由内部重力波（IGW）在恒星内部（例如对流核心或亚表面对流区域）内的对流和辐射区域的界面激发的。我们旨在比较由通过不同统计方法确定的苔丝任务观察到的大量主序列中SLF变异性的性质，并确认SLF变异性的形态与恒星在HR图中的位置之间的相关性。从苔丝观察到的30个巨大恒星的样本中，我们比较了SLF变异性的结果参数，特别是特征频率，从拟合光曲线的振幅光谱获得的特征频率与通过使用Celererite2 Gaussian Process（GP）回归软件（GP）回归软件和浸水的鞋底的光曲线的协方差结构所推断出的幅度曲线。我们发现，使用GP回归与Celerite2仅适用于少数考虑样本的GP回归，从振幅光谱拟合获得的特征频率差异和拟合光曲线的共变性结构的差异。但是，先前报道的SLF变异性的质量，年龄和SLF变异性能之间的趋势仍然不受影响。与文献中使用的先前技术相比，GP回归是一种有效且新颖的方法，可有效地表征大量恒星的SLF变异性。我们得出的结论是，恒星的SLF变异性，尤其是特征频率及其在HR图中的位置之间的相关性对于主要序列巨大恒星具有鲁棒性。大恒星中SLF变异性的随机性也存在分布，这表明SLF变异性的相干性也是质量和大型恒星年龄的函数。
Studies of massive stars using space photometry have revealed that they commonly exhibit stochastic low-frequency (SLF) variability. This has been interpreted as being caused by internal gravity waves (IGWs) excited at the interface of convective and radiative regions within stellar interiors, such as the convective core or sub-surface convection zones. We aim to compare the properties of SLF variability in massive main-sequence stars observed by the TESS mission determined by different statistical methods, and confirm the correlation between the morphology of SLF variability and a star's location in the HR diagram. From a sample of 30 massive stars observed by TESS, we compare the resultant parameters of SLF variability, in particular the characteristic frequency, obtained from fitting the amplitude spectrum of the light curve with those inferred from fitting the covariance structure of the light curve using the celerite2 Gaussian process (GP) regression software and a damped SHO kernel. We find a difference in the characteristic frequency obtained from the amplitude spectrum fitting and from fitting the co-variance structure of the light curve using a GP regression with celerite2 for only a minority of the considered sample. However, the trends among mass, age and the properties of SLF variability previously reported remain unaffected. GP regression is a useful and novel methodology to efficiently characterise SLF variability in massive stars compared to previous techniques used in the literature. We conclude that the correlation between a star's SLF variability, in particular the characteristic frequency, and its location in the HR diagram is robust for main-sequence massive stars. There also exists a distribution in the stochasticity of SLF variability in massive stars, which indicates that the coherency of SLF variability is also a function of mass and age in massive stars.
