论文标题
与发电机过渡连接的晚期型星的旋转尺度缩放尺度的膝关点
A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions
论文作者
论文摘要
晚期恒星的磁活性与它们的旋转速率相关。最多到一定的极限，恒星具有较小的rossby数字，定义为旋转周期除以对流的周转时间，具有较高的活性。对这种旋转活性关系的更详细的看法表明，活动缩放与低杆恒星相比，活动的缩放不是简单的幂律关系，而是对低 - 摩尔斯比恒星的斜率较浅。我们发现，对于色层CAII H＆K活性，这种缩放关系是通过损坏的两件式功率定律很好地建模的。此外，关系的膝关节与轴对称与活性恒星的点活性和表面磁场构型中的非轴对称过渡一致。我们将此膝关点解释为主导轴 - 和非轴对称发电机方案之间的发电机过渡，对旋转的依赖性不同，并根据当前的数值发电机模型讨论了这一假设。
The magnetic activity of late-type stars is correlated with their rotation rates. Up to a certain limit, stars with smaller Rossby numbers, defined as the rotation period divided by the convective turnover time, have higher activity. A more detailed look at this rotation-activity relation reveals that, rather than being a simple power law relation, the activity scaling has a shallower slope for the low-Rossby stars than for the high-Rossby ones. We find that, for the chromospheric CaII H&K activity, this scaling relation is well modelled by a broken two-piece power law. Furthermore, the knee-point of the relation coincides with the axisymmetry to non-axisymmetry transition seen in both the spot activity and surface magnetic field configuration of active stars. We interpret this knee-point as a dynamo transition between dominating axi- and non-axisymmetric dynamo regimes with a different dependence on rotation and discuss this hypothesis in the light of current numerical dynamo models.
