1. Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206, China
2. Department of Astronomy, Beijing Normal University, Beijing 100875, China
3. CAS Key Laboratory of Optical Astronomy, National Astronomical Observotories, Chinese Academy of Sciences, Beijing 100101, China
4. School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China
5. Apache Point Observotory, Sunspot, NM 88349, USA
6. Astronomy Department, New Mexico State University, Las Cruces, NM 88003, USA
7. College of Physics and Electronic Information, Dezhou University, Shandong 253023, China