论文标题
通过在太阳能恒星中的活动区域嵌套来扩增亮度变异性
Amplification of brightness variability by active-region nesting in solar-like stars
论文作者
论文摘要
开普勒的观察结果表明，数百个具有近极基本参数和旋转周期的恒星比太阳具有更强，更常规的亮度变化。在这里，我们确定了这些恒星特殊行为的可能原因。受活动的太阳巢的启发，我们假设这种恒星上活性区域（AR）出现的不均匀程度高于太阳。为了检验我们的假设，我们使用太阳能AR性能和差异旋转，以各种速率和嵌套模式在恒星表面上注入斑点和套头状的AR来对恒星光曲线进行建模。我们表明，从太阳值和嵌套程度的增加相结合的出现频率中等增加可以解释观测到的全部观测到的阳光恒星变异性振幅，几乎是太阳旋转周期。此外，以主动纵向的形式筑巢，其中AR倾向于在两个纵向的附近出现，两种纵向分别以$ 180^\ circ $隔开，导致高度规则，几乎类似正弦的变化模式，与在许多太阳能恒星中观察到的相似。
Kepler observations revealed that hundreds of stars with near-solar fundamental parameters and rotation periods have much stronger and more regular brightness variations than the Sun. Here we identify one possible reason for the peculiar behaviour of these stars. Inspired by solar nests of activity, we assume that the degree of inhomogeneity of active-region (AR) emergence on such stars is higher than on the Sun. To test our hypothesis, we model stellar light curves by injecting ARs consisting of spots and faculae on stellar surfaces at various rates and nesting patterns, using solar AR properties and differential rotation. We show that a moderate increase of the emergence frequency from the solar value combined with the increase of the degree of nesting can explain the full range of observed amplitudes of variability of Sun-like stars with nearly the solar rotation period. Furthermore, nesting in the form of active longitudes, in which ARs tend to emerge in the vicinity of two longitudes separated by $180^\circ$, leads to highly regular, almost sine-like variability patterns, rather similar to those observed in a number of solar-like stars.
