论文标题
具有靠近行星的恒星中的自旋轨道相称性和同步星形活动的模型
A model for spin-orbit commensurability and synchronous starspot activity in stars with close-by planets
论文作者
论文摘要
某些行星托管恒星的旋转周期似乎与距离近距离行星的轨道时期密切相当。提出了一个模型来解释这种现象，该现象是基于恒星内部磁场中谐振振荡的激发，这是通过潮汐电势的组成部分在与恒星旋转的参考框架中非常低的频率。假定位于恒星过冲的层中的磁通管可以研究磁性状态中谐振振荡的激发。该模型认为行星在圆形斜轨道上，并且估计振荡的生长时间尺度。为了使系统与令人兴奋的潜力共振，尽管磁场或潮汐频率的变化，但仍提出了一种自我调节机制。该模型适用于十个系统，并证明可以通过假设$ 10^{2} $和$ 10^{4} $G。具有低质量远处行星的系统，例如AU MIC和HAT-P-11，无法通过提议的模型来解释具有低质量远处的行星的系统，可以考虑到其中八个观察到的近八个系统的可低调性。讨论了系统的自旋轨道演变的后果，包括行星托管恒星的动态潮汐和陀螺仪，并讨论了对星空星际磁相互作用产生的色球特征的影响。
The rotation period of some planet-hosting stars appears to be in close commensurability with the orbital period of their close-by planets. A model is proposed to interpret such a phenomenon based on the excitation of resonant oscillations in the interior magnetic field of the star by a component of the tidal potential with a very low frequency in the reference frame rotating with the star. A magnetic flux tube located in the overshoot layer of the star is assumed to study the excitation of the resonant oscillations in the magnetostrophic regime. The model considers a planet on a circular oblique orbit and the growth timescale of the oscillations is estimated. To keep the system in resonance with the exciting potential, in spite of the variations in the magnetic field or tidal frequency, a self-regulating mechanism is proposed. The model is applied to ten systems and proves capable of accounting for the observed close commensurability in eight of them by assuming a magnetic field between $10^{2}$ and $10^{4}$ G. Systems with low-mass distant planets, such as AU Mic and HAT-P-11, cannot be interpreted by the proposed model. Consequences for the spin-orbit evolution of the systems, including dynamical tides and gyrochronology of planet-hosting stars, are discussed together with the effects on the chromospheric features produced by star-planet magnetic interactions.
