  Our previous study of a system of bodies assumed to move along almost
circular orbits around a central mass, approximately described by Hill's
equations, is extended to "exotic" [alias non-commutative] particles. For a
certain critical value of the angular velocity, the only allowed motions follow
the Hall law. Translations and generalized boosts span two independent
Heisenberg algebras with different central parameters. In the critical case,
the symmetry reduces to a single Heisenberg algebra.
