Null Geodesics in the KerrNewman Metric
Abstract
The photon trajectories in the KerrNewman metric are described in both the black hole and naked singularity cases. The radial motions of photons are discussed, and by finding the turning points of the radial motion, the regions allowed for this motion are determined. The region of negative radii is considered, and it is found that the qualitative differences between the KerrNewman metric and the Kerr metric occur only below the inner horizon and around naked singularities. In some cases stable circular orbits exist in the equatorial plane, and in other cases there are no spherical orbits on positive radii at all.
 Publication:

Bulletin of the Astronomical Institutes of Czechoslovakia
 Pub Date:
 1981
 Bibcode:
 1981BAICz..32..366S
 Keywords:

 Black Holes (Astronomy);
 Geodesic Lines;
 Naked Singularities;
 Particle Motion;
 Photons;
 SpaceTime Functions;
 Circular Orbits;
 Metric Space;
 Particle Trajectories;
 Radii;
 Astrophysics