Mixture model of open clusters in CMD

We developed a rigorous Bayesian frame that treats the open clusters (OC) in CMD as a mixture of members and field stars. The advanced statistics and comprehensive physical models make our method the state of the art of determining the basic properties (Age, Distance, [Fe/H], extinction A_V) along with the slope of MF and the binary fraction of OCs in using photometric data of Gaia EDR3. 

We also accurately determine the binary fraction f_b and γq for NGC3532 by using the mixture model method. For the first time, we unveil that the stars with smaller mass or in the inner region tend to have lower f_b and a more positive value of γ_q due to the lack of low mass ratio binaries. It is strong evidence of the internal dynamics in a cluster.