N-BODY EQUILIBRIUM FIGURES OF EARLY-TYPE GALAXIES .2. ANALYSIS OF ORBITAL POPULATIONS

A detailed analysis of orbital structure has been performed for triaxi al equilibrium configurations (produced by N-body collisionless collap ses) whose axis-ratios are in agreement with predictions inferred from observations of bulges of spirals and elliptical galaxies. We find a relationship between the various projected shapes of the systems (from purely elliptical to pronounced peanuts) and the percentages of vario us kinds of orbits (tube, box, peanut) permissible for equilibrium, ch aracterized by their oscillation frequency ratios along the figure's m ain axes. A link between these percentages and the shape parameter a(4 )/a introduced by Bender is established. The key role of the instabili ty of the x-axial orbit is rediscussed and the importance for the mode l shape determination of vertical bananas bifurcating from it is empha sized.