Spectrum variability of the active solar-type star ξ Bootis A
Spectrum variability of the active solar-type star ξ Bootis A
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活跃太阳型恒星的光谱变异性 Ψ Bootis A
DOI：
10.1093/pasj/psaa002
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发表时间：
2020
影响因子：
2.3
通讯作者：
Hashimoto Osamu
中科院分区：
文献类型：
--
作者：
Takeda Yoichi;Honda Satoshi;Taguchi Hikaru;Hashimoto Osamu
根据2008年12月至2010年5月期间获得的光谱，对天波A（一颗色球活跃的太阳型星星）进行了广泛的光谱研究，目的是探测任何光谱变化并了解其物理来源。对于每个光谱，大气参数的光谱确定的基础上Fe线，和等效宽度（沿着线加宽参数）的99个选定的线进行了测量。我们可以检测到中等强度谱线的等效宽度的有意义的小波动。发现这种变化与有效温度（）相关，与每条线的T敏感性一致，这表明在非均匀条件下的圆盘上平均温度的差异是造成这种变化的主要原因。研究还发现，中等强度谱线的宏观展宽宽度和饱和谱线的等效宽度色散随有效Landé因子的增大而增大，表明磁场的影响。我们的功率谱分析适用于时间序列数据的ViFeiline强度比，并不能证实6.4 d的周期，由以前的研究报告。我们怀疑，在我们观察时，天蝎座A的表面不均匀性与其说是简单的（如单个星星斑块），不如说是相当复杂的（例如，斑点和光斑的复杂聚集体）。
An extensive spectroscopic study on ξ Boo A (a chromospherically active solar-type star) was conducted based on the spectra obtained from 2008 December through to 2010 May, with the aim of detecting any spectrum variability and understanding its physical origin. For each spectrum, the atmospheric parameters were spectroscopically determined based on Fe lines, and the equivalent widths (along with the line-broadening parameters) of 99 selected lines were measured. We could detect meaningful small fluctuations in the equivalent widths of medium-strength lines. This variation was found to correlate with the effective temperature () consistently with theT-sensitivity of each line, which indicates that the difference in the mean temperature averaged over the disk of inhomogeneous condition is mainly responsible for this variability. It was also found that the macrobroadening widths of medium-strength lines and the equivalent widths’ dispersion of saturated lines tend to increase with the effective Landé factor, suggesting the influence of a magnetic field. Our power spectrum analysis applied to the time-sequence data of the ViFeiiline-strength ratio andcould not confirm the 6.4 d period reported by previous studies. We suspect that surface inhomogeneities of ξ Boo A at the time of our observations were not so much simple (such as a single star patch) as rather complex (e.g., intricate aggregate of spots and faculae).