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arXiv 1606.02133astro-ph.SR
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太阳黑子对观测到的太阳声模频移的贡献

On the contribution of sunspots to the observed frequency shifts of solar acoustic modes

A. R. G. Santos, M. S. Cunha, P. P. Avelino, W. J. Chaplin, T. L. Campante

摘要:

30年来,人们已经知道太阳振荡特性中与活动有关的变化。然而,对观测到的变化的不同贡献的相对重要性尚未完全理解。我们的目标是估计从太阳黑子的相对贡献所观察到的活动相关的变化的频率的声学模式。我们用变分原理把太阳黑子引起的声波相位差与全球声波振荡频率的相应变化联系起来。从太阳黑子的属性(面积和纬度作为时间的函数),我们能够估计点引起的频率偏移。然后将这些与与长期太阳周期变化相关的平滑频移分量相结合,并将结果与全球振荡网络组(GONG)数据得出的频移进行比较。这一比较的结果与太阳黑子对观测到的频率偏移的贡献相一致,约为30%,其余70%主要来自全球非随机变化,可能与整个磁场的变化有关。此外,从观测中减去模型频移后得到的残差分析表明,在文献中报道的准两年期变化的数据中存在1.5年的周期性。

英文摘要:

Activity-related variations in the solar oscillation properties have been known for 30 years. However, the relative importance of the different contributions to the observed variations is not yet fully understood. Our goal is to estimate the relative contribution from sunspots to the observed activity-related variations in the frequencies of the acoustic modes. We use a variational principle to relate the phase differences induced by sunspots on the acoustic waves to the corresponding changes in the frequencies of the global acoustic oscillations. From the sunspot properties (area and latitude as a function of time), we are able to estimate the spot-induced frequency shifts. These are then combined with a smooth frequency shift component, associated with long-term solar-cycle variations, and the results compared with the frequency shifts derived from the Global Oscillation Network Group (GONG) data. The result of this comparison is consistent with a sunspot contribution to the observed frequency shifts of roughly 30 per cent, with the remaining 70 per cent resulting mostly from a global, non-stochastic variation, possibly related to the changes in the overall magnetic field. Moreover, analysis of the residuals obtained after the subtraction of the model frequency shifts from the observations indicates the presence of a 1.5-yr periodicity in the data in phase with the quasi-biennial variations reported in the literature.

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。

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