The Investigation of Stationary Points In Central Configuration Dynamics
  A system of N points, each having mass m, and a central mass M forming a planar central configuration, is considered. The equations of motion of a test particle are given and compared using different coordinates. For large values of N, even or odd, the equations are given too. The method used for the computation of some relevant sums can be important for practical applications. It is shown that the stationary solutions (libration points) can be determined from an algebraic equation of 5-th degree. If the mass of the particles is large, the outer libration points disappear. For the inner libration points the limit minimal distance has been detected. If m=M is small the solution obtained for the libration has as limit a solution similar to the for 3-body collinear points. We have also constructed a central configuration with 2N + 1 bodies, in which N new particles, each of mass m1= m, are placed at the libration points of our first system. 
A. E. Rosaev (FGUP NPC "NEDRA" Yaroslavl, Russia)