The Observation and Study of Shallow-contact Binary Systems

The shallow-contact binary is a system with low degree of contact, short orbital period and late spectral type. It is a bridge to connect detached binary system, semi-detached binary system with contact binary system. The study of the common convective envelope (CCE) of shallow-contact binary system is important to know how the CCE comes into being because the CCE of shallow-contact binary system is very thin. We have observed several systems (e.g. RV Psc, AW Vir, II CMa, AD Cnc). And we Study their basic parameters using W-D method. The period studies will help us to understand their structure and evolution.