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arXiv 1107.5564astro-ph.SR
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太阳和类太阳恒星的活动亮度相关

Activity-Brightness Correlations for the Sun and Sun-like Stars

Dora Preminger, Gary Chapman, Angela Cookson

备注：
Accepted by ApJ Letters, 2011
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摘要：

我们分析了太阳特征对三个不同光谱范围内太阳辐照度变化的影响。我们的研究是基于两个太阳周期的价值从圣费尔南多天文台，获得红色，蓝色和钙II K线过滤器的全磁盘测光图像。对于每个图像，我们测量光度总和，Sigma，这是太阳特征对图像的圆盘积分强度的相对贡献。在红、蓝连续统中的光度和Sigma_r和Sigma_b表现出相似的时间模式：它们与太阳活动呈负相关，具有强的短期变率和弱的太阳周期变率。然而，钙II K线光度总和，Sigma_K，是正相关的太阳活动，并有强烈的变化，太阳周期的时间尺度。我们表明，我们可以模拟太阳的热通量的变化作为一个线性组合的Sigma_r和Sigma_K。我们推断，在太阳周期的时间尺度上，太阳的辐射热辐照度的变化是直接相关的谱线的变化，但与连续变化呈负相关。我们的蓝色和红色连续滤光片与用于测量恒星光度变化的Strömgren b和y滤光片非常相似。我们的结论是，活跃的恒星，其可见光连续亮度与活动成反比变化，测量的Ca HK指数，显示出一种模式，这是类似于太阳，即在可见光连续辐射的变化是斑点为主。

英文摘要：

We analyze the effect of solar features on the variability of the solar irradiance in three different spectral ranges. Our study is based on two solar-cycles' worth of full-disk photometric images from the San Fernando Observatory, obtained with red, blue and Ca II K-line filters. For each image we measure the photometric sum, Sigma, which is the relative contribution of solar features to the disk-integrated intensity of the image. The photometric sums in the red and blue continuum, Sigma_r and Sigma_b, exhibit similar temporal patterns: they are negatively correlated with solar activity, with strong short-term variability and weak solar-cycle variability. However, the Ca II K-line photometric sum, Sigma_K, is positively correlated with solar activity and has strong variations on solar-cycle timescales. We show that we can model the variability of the Sun's bolometric flux as a linear combination of Sigma_r and Sigma_K. We infer that, over solar-cycle timescales, the variability of the Sun's bolometric irradiance is directly correlated with spectral line variability, but inversely correlated with continuum variability. Our blue and red continuum filters are quite similar to the Strömgren b and y filters used to measure stellar photometric variability. We conclude that active stars whose visible continuum brightness varies inversely with activity, as measured by the Ca HK index, are displaying a pattern that is similar to that of the Sun, i.e. radiative variability in the visible continuum that is spot-dominated.

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