Motion of four co-orbital satellites and four test particles (arcs) around Neptune, without Galatea. The figure shows the orbital radius (km) vs. longitude (deg) in a frame rotating with the most massive Lagrangian satellite S₁ (diameter =10.4 km, assuming a density of 1 g cm^-3). The other satellites S₂, S₃, and S₄ have diameters of 2.2, 2.8, and 2.3 km, respectively. Integration time is 150 years. The co-orbital bodies are in a stable stationary configuration. The system of co-orbital satellites and arcs is ≃0.25 km outside the CIR, as given by the observations.