论文标题
太阳型星的磁场演变
Magnetic field evolution in solar-type stars
论文作者
论文摘要
我们讨论有关太阳能恒星磁场演化的选定方面。具有活性循环的大多数恒星都在标准化的色圈钙发射随反向rossby数线性增加的范围内。对于低于太阳值的四分之一的Rossby数字，活动饱和，没有发现周期。对于高于太阳值的罗斯比数字，又没有发现活动周期，但是现在，对于恒星的很大一部分，活动再次上升。迅速旋转的恒星显示出非轴对称的大规模磁场，但是模型与观察到有关Rossby数的实际值的观察之间存在分歧。我们还讨论了使用各种线性极化技术在恒星表面检测磁性螺旋性的迹象，使用奇偶校验对线性极化的贡献，并使用法拉第旋转在表面上方。
We discuss selected aspects regarding the magnetic field evolution of solar-type stars. Most of the stars with activity cycles are in the range where the normalized chromospheric Calcium emission increases linearly with the inverse Rossby number. For Rossby numbers below about a quarter of the solar value, the activity saturates and no cycles have been found. For Rossby numbers above the solar value, again no activity cycles have been found, but now the activity goes up again for a major fraction of the stars. Rapidly rotating stars show nonaxisymmetric large-scale magnetic fields, but there is disagreement between models and observations regarding the actual value of the Rossby number where this happens. We also discuss the prospects of detecting the sign of magnetic helicity using various linear polarization techniques both at the stellar surface using the parity-odd contribution to linear polarization and above the surface using Faraday rotation.
