论文标题
检测二进制恒星中的长时间活性最小。 $ζ^{2} $ ret的情况
Detecting prolonged activity minima in binary stars. The case of $ζ^{2}$ Ret
论文作者
论文摘要
语境。众所周知，从1645年到1715年，太阳能活动尤其低，并且日光点的数量极大地减少。这个时期被称为Maunder最低（mm）。像MM一样长时间活性极小的恒星的研究可能有助于阐明这个神秘的时代。 目标。探索属于二进制系统的星$ζ^{2} $ ret处于类似于MM的状态。在2000年至2019年之间，我们收集了超过430多个光谱，其中包括竖琴，Reosc，Uves和Feros光谱仪。 方法。我们使用Mount Wilson指数对两个组件进行了详细的长期活动研究，该研究是从Ca II H \＆K线中获得的。为了搜索活动周期的迹象，我们通过广义的伦敦量表和清洁期刊分析了所得的时间序列。 结果。我们的光谱分析显示了Zet01 RET的高活性水平，磁性活性周期幅度的显着下降为$ζ^{2} $ ret。因此，与先前报道的值相比，这两个组件之间的活性差异略有增加（$δ$ log（RHK）$ \ sim $ 0.24 DEX）。这里分析的长期系列使我们能够重新计算并将$ζ^{2} $ ret的周期限制为$ \ sim $ 7.9 yr。我们还检测到了$ \ sim $ 4.2 yr in $ζ^{1} $ ret的长期活动周期。 结论。通过类比，我们建议在MM期间提出的太阳周期较弱的情况，我们建议$ζ^{2} $ ret显示的活动特征，即，与其出色的伴侣相比，活动水平非常低，这是一个明显降低的振幅（$ \ sim $ 47％），并且可以证明该星星可以证明这是一个稳定的状态。据我们所知，这是第一个通过二进制系统中高度差异的活动行为检测到的第一个MM候选星。
Context. It is well known that from 1645 to 1715 solar activity was notably low and the number of sunspots was extremely reduced. This epoch is known as the Maunder Minimum (MM). The study of stars in prolonged activity minima like the MM could help to shed light on this enigmatic epoch. Aims. To explore if the star $ζ^{2}$ Ret, which belongs to a binary system, is in a state similar to the MM. We have collected more than 430 spectra acquired between 2000 and 2019 with the HARPS, REOSC, UVES, and FEROS spectrographs. Methods. We performed a detailed long-term activity study of both components using the Mount Wilson index, which is obtained from the Ca II H\&K lines. To search for signs of an activity cycle, we analyzed the resulting time-series with the Generalized Lomb-Scargle and CLEAN periodograms. Results. Our spectroscopic analysis shows a high activity level for zet01 Ret and a significant decrease in the magnetic activity cycle amplitude of $ζ^{2}$ Ret. Thus, the activity difference between both components has been slightly increased ($Δ$log (RHK) $\sim$0.24 dex), when compared to the previously reported value. The long series analyzed here allowed us to recalculate and constrain the period of $ζ^{2}$ Ret to $\sim$7.9 yr. We also detected a long-term activity cycle of $\sim$4.2 yr in $ζ^{1}$ Ret. Conclusions. By analogy with the scenario that proposes a weak solar cycle during the MM, we suggest that activity signatures showed by $ζ^{2}$ Ret, i.e., a very low activity level when compared to its stellar companion, a notably decreasing amplitude ($\sim$47%), and a cyclic behaviour, are possible evidence that this star could be in a MM state. It is, to our knowledge, the first MM candidate star detected through a highly discrepant activity behaviour in a binary system.
