arXiv 2102.021352021-02-03astro-ph.SR

三维恒星大气模拟中光度和光谱振荡幅度之间的关系

The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations

Yixiao Zhou, Thomas Nordlander, Luca Casagrande, Meridith Joyce, Yaguang Li, Anish M. Amarsi, Henrique Reggiani, Martin Asplund

备注：: 16 pages, 7 figures, accepted for publication in MNRAS
DOI：: 10.1093/mnras/stab337

阅读 PDF

arXiv 页面 ↗HTML 原文 ↗

摘要：

我们建立了一个定量的光度和光谱检测的类太阳振荡之间的关系，使用从头算，三维（3D），恒星大气的流体动力学数值模拟。我们提出了一个理论推导作为我们的方法的概念证明。我们进行现实的谱线形成计算，以量化光度和径向速度幅度的两个案例研究：太阳和红巨星$ε$头之间的比率。亮度振幅是根据三维模拟预测的热辐射通量计算的，其中颗粒背景的建模方式与小行星地震观测相同。径向速度振幅是由合成谱线的波长偏移确定的，方法与BiSON和SONG观测中使用的方法非常相似。因此，理论上的光度与径向速度振幅比可以直接与相应的观测结果相比较。对于太阳，我们预测BiSON和SONG的理论比值分别为21.0和23.7 ppm/[m/s]，与观测值19.1和21.6 ppm/[m/s]非常一致。对于$ε$ Tau，我们预测K2和SONG比率为48.4 ppm/[m/s]，再次与观测值42.2 ppm/[m/s]良好一致，并且比传统经验标度关系的结果（给出23.2 ppm/[m/s]）有很大改进。因此，这项研究通过详细的3D恒星大气建模，为定量了解太阳振荡开辟了道路。

英文摘要：

We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant $ε$ Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the same way as asteroseismic observations. Radial velocity amplitudes are determined from the wavelength shift of synthesized spectral lines with methods closely resembling those used in BiSON and SONG observations. Consequently, the theoretical luminosity to radial velocity amplitude ratios are directly comparable with corresponding observations. For the Sun, we predict theoretical ratios of 21.0 and 23.7 ppm/[m/s] from BiSON and SONG respectively, in good agreement with observations 19.1 and 21.6 ppm/[m/s]. For $ε$ Tau, we predict K2 and SONG ratios of 48.4 ppm/[m/s], again in good agreement with observations 42.2 ppm/[m/s], and much improved over the result from conventional empirical scaling relations which gives 23.2 ppm/[m/s]. This study thus opens the path towards a quantitative understanding of solar-like oscillations, via detailed modelling of 3D stellar atmospheres.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文