Characterizing motion types of G-band bright points in the quiet Sun

作     者：Yun-Fei Yang Hui-Xue Qu Kai-Fan Ji Song Feng Hui Deng Jia-Ben Lin Feng Wang 

作者机构：Faculty of Information Engineering and Automation / Yunnan Key Laboratory of Computer Technology ApplicationKunming University of Science and Technology Key Laboratory of Solar ActivityNational Astronomical ObservatoriesChinese Academy of Sciences Key Laboratory of Modern Astronomy and AstrophysicsNanjing UniversityMinistry of Education Yunnan ObservatoriesChinese Academy of Sciences 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2015年第15卷第4期

页      面：569-582页

核心收录：

学科分类：0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 070401[理学-天体物理] 0825[工学-航空宇航科学与技术] 0704[理学-天文学] 

基　　金：Supported by the National Natural Science Foundation of China 

主　　题：techniques: image processing    Sun: photosphere    methods: dataanalysis    methods: statistical 

摘      要：We study the motion of G-band bright points （GBPs） in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT） is used, and GBPs are automat- ically tracked by segmenting 3D evolutional structures in a space-time cube. After putting the GBPs that do not move during their lifetimes aside, the non-stationary GBPs are categorized into three types based on an index of their motion type. Most GBPs that move in straight or nearly straight lines are categorized as a straight mo- tion type, a few moving in rotary paths into rotary motion, and the others fall into a motion type we called erratic. The mean horizontal velocities are 2.18±0.08 km s-1, 1.63±0.09km s^-1 and 1.33±0.07 km s^-1 for straight, erratic and rotary motion types, respectively. We find that a GBP drifts at a higher and constant velocity during its whole life if it moves in a straight line. However, it has a lower and variational velocity if it moves on a rotary path. The diffusive process is ballistic-, super- and sub-diffusion for straight, erratic and rotary motion types, respectively. The corresponding diffusion index （γ） and coefficients （K） are 2.13±0.09 and 850±37km^2 s^-1, 1.82±0.07 and 331 ±24 km^2 s^-1, and 0.73±0.19 and 13±9 km^2 s^-1. In terms of direction of motion, it is homogeneous and isotropic, and usually persists between neighboring frames, no matter what motion type a GBP is classified as.