ORBIT CLASSIFICATION IN ARBITRARY 2D AND 3D POTENTIALS

A method of classifying generic orbits in arbitrary 2D and 3D potentia ls is presented. It is based on the concept of spectral dynamics intro duced by Binney & Spergel that uses the Fourier transform of the time series of each coordinate. The method is tested using a number of pote ntials previously studied in the literature and is shown to distinguis h correctly between regular and irregular orbits, to identify the vari ous families of regular orbits (boxes, loops, tubes, boxlets, etc.), a nd to recognize the second-rank resonances that bifurcate from them. T he method returns the position of the potential centre and, for 2D pot entials, the orientation of the principal axes as well, should this be unknown. A further advantage of the method is that it has been encode d in a FORTRAN program that does not require user intervention, except for 'fine tuning' of search parameters that define the numerical limi ts of the code. The automatic character makes the program suitable for classifying large numbers of orbits.