1. Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216, P. R. China
2. Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216, P. R. China
3. Graduate University of the Chinese Academy of Sciences, Yuquan Road 19, Sijingshang Block, 100049 Beijing City, China
4. Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata, Pcia. Bs. As., Argentina
5. Instituto de Astrofísica de La Plata (CCT La plata - CONICET/UNLP), Argentina
6. Sternberg Astronomical Institute, Moscow State University, Universitetskij prospect 13, Moscow 119992, Russia