标题： K2中低质量恒星的光变曲线调制。 I. 太阳邻域中508个快速旋转体的识别 显示英文标题

标题： Light Curve Modulation of Low Mass Stars in K2. I. Identification of 508 Fast Rotators in the Solar Neighborhood

摘要： K2任务旨在针对大量附近的（d<100 pc）GKM矮星，这些恒星是从SUPERBLINK自行调查中选择的（mu>40 mas yr^-1，V<20）。 此外，该任务还针对与本地（d<500 pc）银河晕种群相关的低质量、高自行运动的恒星，这些恒星同样从SUPERBLINK中选择。 K2任务的第0至第8次观测活动总共监测了27,382颗这些冷主序星。 我们使用自相关函数通过在K2光变曲线中识别短周期的光度调制来搜索快速旋转的恒星。 我们识别出508个候选快速旋转恒星，其旋转周期小于4天，并且光变曲线调制与恒星黑子一致。 它们的动力学特性显示平均横向速度较低，表明它们属于年轻的盘状星族。 快速旋转恒星中的一小部分（13个）被发现在颜色和动力学特性与本地银河晕种群一致的目标中，可能代表由于密近双星系统中的潮汐相互作用而被加速旋转的恒星。 我们进一步证明从K2光变曲线中选择的M型矮星快速旋转恒星更有可能具有紫外线过量，并讨论了K2任务基于快速旋转率识别新的附近年轻GKM矮星的潜力。 最后，我们讨论了本地晕星作为开普勒观测区域中参考性、非变源的潜在用途。 显示英文摘要

摘要： The K2 mission is targeting large numbers of nearby (d<100 pc) GKM dwarfs selected from the SUPERBLINK proper motion survey (mu>40 mas yr^-1, V<20). Additionally, the mission is targeting low-mass, high proper motion stars associated with the local (d<500 pc) Galactic halo population also selected from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 27,382 of these cool main-sequence stars. We used the auto-correlation function to search for fast rotators by identifying short-period photometric modulations in the K2 light curves. We identified 508 candidate fast rotators with rotation periods <4 days that show light curve modulations consistent with star spots. Their kinematics show low average transverse velocities, suggesting they are part of the young disk population. A subset (13) of the fast rotators are found among those targets with colors and kinematics consistent with the local Galactic halo population and may represent stars spun up by tidal interactions in close binary systems. We further demonstrate the M dwarf fast rotators selected from the K2 light curves are significantly more likely to have UV excess, and discuss the potential of the K2 mission to identify new nearby young GKM dwarfs on the basis of their fast rotation rates. Finally, we discuss the possible use of local halo stars as fiducial, non-variable sources in the Kepler fields.