ON THE INTEGRABILITY OF HALO DIPOLES IN GRAVITY

We stress that halo dipole components are nontrivial in core-halo syst ems in both Newton's gravity and general relativity. To this end, we e xtend a recent exact relativistic model to include also a halo dipole component. Next, we consider orbits evolving in the inner vacuum betwe en a monopolar core and a pure halo dipole and find that, while the Ne wtonian dynamics is integrable, its relativistic counterpart is chaoti c. This shows that chaoticity due only to halo dipoles is an intrinsic relativistic gravitational effect. (C) 1997 Elsevier Science B.V.