2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/96859The Newtonian as well as the special relativistic dynamics are used to study the stability of orbits of a test particle moving around a black hole plus a dipolar halo. The black hole is modeled by either the usual monopole potential or the Paczynki-Wiita pseudo-Newtonian potential. The full general relativistic similar case is also considered. The Poincare section method and the Lyapunov characteristic exponents show that the orbits for the pseudo-Newtonian potential models are more unstable than the corresponding general relativistic geodesics.RevTEX, 7 eps figures, to appear in Astron AstrophysAstrophysicsGeneral Relativity and Quantum CosmologyChaotic Dynamicstext