Timelike and null equatorial geodesics in the Bonnor-Sackfield relativistic disk

abstract. a study of timelike and null equatorial geodesics in the bonnor- sackfield relativistic thin disk is presented. the motion of test particles in the equatorial plane is analyzed, both for the newtonian thin disk model as for the corresponding relativistic disk. the nature of the possible orbits is studied by means of a qualitative analysis of the effective potential and by numerically solving the motion equation for radial and non-radial equatorial trajectories. the existence of stable, unstable and marginally stable circular orbits is analyzed, both for the newtonian and relativistic case. examples of the numerical results, obtained with some simple values of the parameters, are presented.