Dynamics in the xy plane of the precessing model with mass bar GM_b = 0.1 and tilt angle ε = 0, for which the major axis of the bar rotates counterclockwise inside this plane. Top: Lagrange points and zero velocity curves for Jacobi constant C_J = −0.1876 (Ferrers bar of the model is outlined by the blue curve). Centre: in orange lines, family of periodic orbits of the mode, Ferrers bar in blue. Bottom: in blue, unstable invariant manifolds. In red, Lagrange points of the system.