Carter-like constants of the motion in Newtonian gravity and electrodynamics.
For a test body orbiting an axisymmetric body in Newtonian gravitational theory with mass m and multiple moments Q_{l} (and for a charge in orbit about a charge distribution with the same multipole moments) we show that there exists, in addition to the energy and angular momentum component along the symmetry axis, a conserved quantity analogous to the Carter constant of Kerr spacetimes for rotating black holes in general relativity, if the odd-l moments vanish, and the even-l moments satisfy Q_{2l}=m(Q_{2}/m);{l}. Strangely, this is precisely the relation among mass moments enforced by the no-hair theorems of rotating black holes. By contrast, if Newtonian gravity is supplemented by a multipolar gravitomagnetic field, whose leading term represents frame dragging, we are unable to find an analogous Carter-like constant. This further highlights the special nature of the Kerr geometry.
Will
Clifford M
CM
GReCO, Institut d'Astrophysique de Paris, CNRS, Université Pierre et Marie Curie, 98 bis Bd. Arago, 75014 Paris, France. cmw@wuphys.wustl.edu