e) Ring Symmetry and the Presence of Outer Debris
Table 1 also includes an estimate of the degree of asymmetry of the ring and the amount of outer debris around the galaxy which does not appear to be associated with either the ring or disk component. The degree of ring asymmetry was estimated by determining whether the ring was brighter or more extended on one side of the disk than the other. The determination of the amount of outer debris was especially difficult since it depends sensitively on the type of "plate material" available. We have therefore chosen not to report the quality 3 determinations because most of them were for objects where either CCD images or SRC plates were not available.
The presence of asymmetric rings and/or outer debris may indicate that the system is relatively young, and has not had a chance to settle into an equilibrium. The fact that the two parameters show a fair correlation with each other (correlation coefficient = 0.61 for 15 objects; 1.5% chance of being from a random distribution) provides some evidence for this interpretation. The weak correlation between the angle and the asymmetry of the ring (Section IIIc) suggests that all three parameters may provide information about the age of polar-ring galaxies.