Characterization of planar symmetric central configurations of four bodies, models, and an application

Abstract: We overview angle-based models to study planar symmetric central configurations of four bodies. We present models to determine the masses given the shape of the configuration and the shape-type of the configuration given the masses. We also describe a diagram-based method for the counting of the shape-types in the case of the concave configurations. As an application, we determine planar symmetric central configurations containing bodies of Earth's and Moon's masses.