Following the application of knowledge gained from studies of stellar evolution and stellar atmospheres to binary studies in the 1950s and 60s, mankind began to probe into the physics behind binary systems and their evolution. Relevant theories started being formulated in the 1970s, which was also when Yunnan Observatories started showing an interest in this field. Over the past few decades, the binaries & variables group has observed and studied many such objects, most notably W Ursae Majoris variables, and made considerable discoveries in the field. 

　　The main research activities of the group include using instruments such as our 2.4m telescope, as well as the already-established international binary survey project, to systematically observe and study close binaries in various stages of evolution. It is expected that such studies should yield a rich mine of information concerning brown dwarfs and black holes, the interaction between extrasolar planets and their host stars, and the formation and evolution of binary systems in general. 

    Current research interests of the group are as follows: 

1. Research of late-type tidally/magnetically locked binaries during key evolutionary stages, the identity of their companion stars, and the companion environment, activity, and evolution of W Ursae Majoris variables in general. 
2. Research on white dwarfs, neutron stars, black holes and other dense objects, with a special focus on what has become of the first stars, massive star(>100 solar masses) remnants and other prospective black hole progenitors. 
3. The mechanisms behind unstable objects such as cataclysmic variables and X-ray binaries. 
4. The search for and study of brown dwarfs and planets in extrasolar systems, the search for such objects outside compact binaries, and to provide constraints on the structure and evolution of, as well as the interaction between, stellar systems; the systematic search for and study of brown dwarfs and planets beyond G, K and M type binaries, and to study the effects of the activity of stars in binary systems on their planets. 
5. To observe and analyze compact binaries and pulsars in clusters and extragalactic sources, to measure their distance, and to study the trends of formation, evolution, and interaction of such objects in different environments. 
6. The study of massive binaries, including the impact of stellar winds, matter exchange, and other physical processes on their structure and evolution, as well as their potential as GRB progenitors. 

　　Link to Chinese website: http://www.ynao.ac.cn/jgsz/kybm/sxybxyjtz/jj/