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arXiv 1401.6239astro-ph.SR
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类太阳恒星上层的局部扰动:对声振荡谱的影响

Local perturbations of the upper layers of a Sun-like star: the impact on the acoustic oscillation spectrum

Ana Brito, Ilidio Lopes

摘要:

在过去十年中,天基飞行任务提供的观测性小行星地震数据的质量和数量都有了巨大的提高。确定星震参数以估计恒星内部发生的基本物理过程,今天可以以前所未有的方式完成。在这项工作中,我们提出了计算地震观测$β$,这是一个代理的声学模式传播的包络线的类太阳恒星的相移。该地震参数$β$可用于识别通常称为毛刺的快速变化区域。我们发现,一个小的变化,在结构中,小于1%的声速,产生一个毛刺的声学潜力,可以解释的振荡字符的$β$。这种方法使我们能够精确地确定毛刺的位置和厚度。我们将这个想法应用到类太阳恒星$α$半人马座A上,发现了一个位于大约$0.94\,R$(1400 s)处的毛刺,厚度为恒星半径的0.2%。这与数据完全一致,也验证了其他地震测试。

英文摘要:

In the last decade the quality and the amount of observational asteroseismic data that has been made available by space based missions had a tremendous upgrowth. The determination of asteroseismic parameters to estimate the fundamental physical processes occurring in stars' interiors, can be done today in a way that has never been possible before. In this work we propose to compute the seismic observable $β$, which is a proxy of the phase shift of the acoustic modes propagating in the envelope of the Sun-like stars. This seismic parameter $β$ can be used to identify rapid variation regions usually known as glitches. We show that a small variation in the structure, smaller than 1% in the sound speed, produces a glitch in the acoustic potential that could explain the oscillatory character of $β$. This method allows us to determine the location and the thickness of the glitch with precision. We applied this idea to the Sun-like star $α$ Centauri A and found a glitch located at approximately $0.94\,R$ (1400 s) and with a thickness of 0.2% of the stars' radius. This is fully consistent with the data and also validates other seismic tests.

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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