Beili Ying^1,2, Alessandro Bemporad³, Silvio Giordano³, Paolo Pagano⁴, Li Feng¹, Lei Lu¹, Hui Li¹ and Weiqun Gan¹, (1)Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China, (2)University of Science and Technology of China, School of Astronomy and Space Sciences, Hefei, China, (3)INAF-Osservatorio Astrofisico di Torino, Pino Torinese, Italy, (4)University of St. Andrews, School of Mathematics and Statistics, St. Andrews, United Kingdom