GENERALIZED INVESTIGATION OF THE ROTATION–ACTIVITY RELATION: FAVORING ROTATION PERIOD INSTEAD OF ROSSBY NUMBER
GENERALIZED INVESTIGATION OF THE ROTATION–ACTIVITY RELATION: FAVORING ROTATION PERIOD INSTEAD OF ROSSBY NUMBER
复制标题
轮换与活动关系的广义研究：支持轮换周期而不是罗斯比数
DOI：
10.1088/0004-637x/794/2/144
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Passegger
中科院分区：
文献类型：
--
作者：
Reiners;Schüssler;Passegger
类太阳和低质量恒星的磁场活动导致X射线日冕发射，这种发射在旋转速度更快的恒星中更强。这种关系通常用Rossby数来解释，即旋转周期与对流翻转时间的比值。我们根据观测到的821颗质量低于1.4 M的恒星的X射线发射和自转周期重新考虑了这一解释。广义分析的X射线光度归一化的辐射热光度，LX/L博尔，旋转周期，P和恒星半径，R的组合之间的关系，表明Rossby制定不提供最小的散射的解决方案。相反，我们发现关系L X/L bol P− 2 R− 4最佳地描述了恒星的不饱和部分。这个关系式等价于L X <$P− 2，表明旋转周期单独决定了总的X射线发射。由于L X与恒星表面的磁通量直接相关，这意味着表面磁通量仅由星星的自转决定，与其他恒星参数无关。而如果对流翻转时间恰好为
Magnetic activity in Sun-like and low-mass stars causes X-ray coronal emission which is stronger for more rapidly rotating stars. This relation is often interpreted in terms of the Rossby number, ie, the ratio of rotation period to convective overturn time. We reconsider this interpretation on the basis of the observed X-ray emission and rotation periods of 821 stars with masses below 1.4 M☉. A generalized analysis of the relation between X-ray luminosity normalized by bolometric luminosity, L X/L bol, and combinations of rotational period, P, and stellar radius, R, shows that the Rossby formulation does not provide the solution with minimal scatter. Instead, we find that the relation L X/L bol∝ P− 2 R− 4 optimally describes the non-saturated fraction of the stars. This relation is equivalent to L X∝ P− 2, indicating that the rotation period alone determines the total X-ray emission. Since L X is directly related to the magnetic flux at the stellar surface, this means that the surface flux is determined solely by the star's rotation and is independent of other stellar parameters. While a formulation in terms of a Rossby number would be consistent with these results if the convective overturn time scales exactly as