Exploring the Evolution of Stellar Rotation Using Galactic Kinematics
Exploring the Evolution of Stellar Rotation Using Galactic Kinematics
复制标题
利用银河运动学探索恒星旋转的演化
作者：
R. Angus;A. Beane;A. Price;E. Newton;J. Curtis;T. Berger;J. V. van Saders;Rocio Kiman;D. Foreman;Y. Lu;L. Anderson;J. Faherty
冷矮星的自转演化在101 - 2 Gyr之后受到很大的限制，因为缺乏老主序星的精确年龄和自转周期。在这项工作中，我们使用速度色散作为年龄代理，以揭示温度依赖的旋转演化的低质量开普勒矮星，并证明运动学年龄可能是一个有用的工具，在未来校准陀螺年代学。我们发现，一个线性gyrochronology模型，校准，以适应的周期关系的Praesepe集群，不适用于恒星年龄超过约1 Gyr。虽然晚K矮星在年轻时比早K矮星旋转得慢，但在老年时，我们发现晚K矮星的旋转速度与同龄的早K矮星相同或更快。这一结果同意定性与半经验模型，改变表面到核心的角动量传输率作为时间和质量的函数。它也与最近对NGC 6811星团中恒星的观测一致，这表明K矮星的表面旋转速率经历了一个受抑制的进化时期。我们发现，最古老的开普勒恒星与测量的旋转周期晚K和早期M矮星，这表明这些恒星保持斑点表面和保持磁活跃的时间比更大质量的恒星。最后，基于它们的运动学，我们确认许多快速旋转的GKM矮星很可能是同步双星。
The rotational evolution of cool dwarfs is poorly constrained after ∼1–2 Gyr due to a lack of precise ages and rotation periods for old main-sequence stars. In this work, we use velocity dispersion as an age proxy to reveal the temperature-dependent rotational evolution of low-mass Kepler dwarfs and demonstrate that kinematic ages could be a useful tool for calibrating gyrochronology in the future. We find that a linear gyrochronology model, calibrated to fit the period– relationship of the Praesepe cluster, does not apply to stars older than around 1 Gyr. Although late K dwarfs spin more slowly than early-K dwarfs when they are young, at old ages, we find that late K dwarfs rotate at the same rate or faster than early-K dwarfs of the same age. This result agrees qualitatively with semiempirical models that vary the rate of surface-to-core angular momentum transport as a function of time and mass. It also aligns with recent observations of stars in the NGC 6811 cluster, which indicate that the surface rotation rates of K dwarfs go through an epoch of inhibited evolution. We find that the oldest Kepler stars with measured rotation periods are late K and early M dwarfs, indicating that these stars maintain spotted surfaces and stay magnetically active longer than more massive stars. Finally, based on their kinematics, we confirm that many rapidly rotating GKM dwarfs are likely to be synchronized binaries.
影响因子：
5.3
作者：
Berger, Travis A.;Huber, Daniel;Kraus, Adam L.
通讯作者：
Kraus, Adam L.