Asteroseismology of 19 low-luminosity red giant stars from Kepler
Asteroseismology of 19 low-luminosity red giant stars from Kepler
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DOI：
10.1051/0004-6361/201628311
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发表时间：
2016-05
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影响因子：
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通讯作者：
F. P. Hernández;R. García;E. Corsaro;S. Triana;J. Ridder
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文献类型：
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作者：
F. P. Hernández;R. García;E. Corsaro;S. Triana;J. Ridder
上下文。由于美国宇航局开普勒任务提供的长期连续观测，现在可以高精度地确定红巨星的声学和混合模式频率。在这里，我们考虑Corsaro等人（2015）选择的19颗低光度红巨星的特征频率，进行详细的峰值bagging分析。目标。我们的目标是通过使用单个模式频率和光谱信息来获得恒星参数。方法。我们使用了一种基于最小化程序的正演建模技术，结合了p模式的频率、偶极模式的周期间隔和光谱数据。结果。正演模拟的结果与地震标度关系得到的结果一致，但正演模拟的误差较小。log g的平均误差为0.002个指数，相比之下，最大功率频率为0.011个指数，νmax，光谱分析为0.10个指数。质量和半径的相对误差平均分别为2%和0.5%，而由标度关系得出的相对误差分别为3%和2%。无法确定初始氦丰度和混合长度参数。最后，对于给定物理输入的模型网格，我们发现低质量恒星需要更高的超冲参数值。
Context. Frequencies of acoustic and mixed modes in red giant stars are now determined with high precision thanks to the long continuous observations provided by the NASA’s Kepler mission. Here we consider the eigenfrequencies of nineteen low-luminosity red giant stars selected by Corsaro et al. (2015) for a detailed peak-bagging analysis. Aims. Our objective is to obtain stellar parameters by using individual mode frequencies and spectroscopic information. Methods. We use a forward modelling technique based on a minimization procedure combining the frequencies of the p modes, the period spacing of the dipolar modes, and the spectroscopic data. Results. Consistent results between the forward modelling technique and values derived from the seismic scaling relations are found but the errors derived using the former technique are lower. The average error for log g is 0.002 dex, compared to 0.011 dex from the frequency of maximum power, νmax, and 0.10 dex from the spectroscopic analysis. Relative errors in the masses and radii are on average 2% and 0.5% respectively, compared to 3% and 2% derived from the scaling relations. No reliable determination of the initial helium abundances and the mixing length parameters could be made. Finally, for our grid of models with a given input physics, we found that low-mass stars require higher values of the overshooting parameter.