The circular restricted 4-body problem with three equal primaries in the collinear central configuration of the 3-body problem

We study the dynamics of the circular restricted 4-body problem with three primaries with equal masses at the collinear configuration of the 3-body problem with an infinitesimal mass. We calculate the equilibrium points and study their linear stability. By applying the Lyapunov theorem, we prove the existence of periodic orbits bifurcating from the equilibrium points and, further, prove that they continue in the full 4-body problem. Moreover, we prove analytically the existence of Hill and of comet-like periodic orbits.