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What Determines the Relative Areas of Spots and Faculae on Sun-like Stars?

机译:是什么决定了太阳类恒星上的斑点和浅斑的相对面积?

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We analyze newly digitized Ca K plage area data extending back to 1915, and also the white-light facular area data beginning in 1874, to investigate further our earlier finding that the area ratio of faculae to spots decreases at increasing activity levels. We find that this ratio decreases in plage as well as facular data, so it cannot be an artifact of the visibility function of limb faculae. The decrease is also accentuated in daily data, compared to annual means; we explain this as a consequence of the different dependences of facular, plage, and spot lifetimes upon their emergent magnetic flux. From this we show that subphotospheric field properties are more likely to determine this ratio, rather than photospheric field diffusion rates. Systematic, cycle-to-cycle variations in its value suggest an origin in fluctuations of the field generation mechanism; specifically, a mechanism that produces a positive correlation between magnetic flux generation efficiency, and relative power in the spatial spectrum at low frequencies. Our results also suggest that main-sequence stars about 50% more magnetically active than the present Sun might exhibit ratio values an order of magnitude lower than current solar values. This evidence strengthens our earlier argument that a rapid shift toward dark photospheric structures in both active regions and network provides the most likely explanation of the recently reported sharp increase of photometric variability in late-type stars somewhat more active than the Sun.
机译:我们分析了可追溯到1915年的新数字化Ca K斑块面积数据,以及1874年开始的白光望远镜面积数据,以进一步调查我们更早的发现,即随着活动水平的提高,斑点与斑点的面积比降低。我们发现,该比率在斑块和眼部数据中均下降,因此它不能成为肢状角膜可见功能的假象。与年度平均值相比,每日数据也明显减少了。我们之所以解释这一点,是因为它们的出射磁通量不同,它们的寿命不同。由此可见,亚光球场特性更可能决定该比率,而不是光球场扩散率。其值的系统的,逐周期的变化表明磁场产生机理的波动是起源。具体而言,是一种在低频下在磁通产生效率与空间频谱中的相对功率之间产生正相关的机制。我们的结果还表明,与当前太阳相比,主序恒星的磁活度大约高50%,其比值可能比当前太阳值低一个数量级。这一证据强化了我们先前的论点,即活跃区域和网络都向暗光球结构的快速转变提供了最有可能的解释,即最近报道的晚型恒星的光度学变异性急剧增加,而后者比太阳活跃得多。

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