6. Conclusions and future work
We have compared the results in the UESAC 1992 and 1993 surveys with the PLS survey and with 5297 numbered EMP/MPC asteroids.
The statistics of the apparent and absolute magnitudes show that the slopes of the and curves are similar but not identical in the different surveys. This is also true for the slopes of the curves. The statistics of the three orbital elements semi-major axis, eccentricity and inclination show no major differences between UESAC, PLS and EMP/MPC asteroids. The statistics of the semi-major axis for the UESAC and PLS asteroids larger than certain completness thresholds ( for UESAC, for PLS) indicate that the asteroids in the outer belt are more numerous. We show that the alignment with Jupiter's longitude of perihelion seen for the numbered EMP/MPC asteroids cannot be seen for the asteroids in UESAC and PLS larger than the above mentioned completness thresholds. The alignment with Jupiter is, however, still present for the larger EMP/MPC () asteroids. We raise the question if this could be a difference between large more primordial bodies and small collisional fragments; most UESAC and PLS asteroids are smaller than .
Future work should be done in understanding the reason for the statistical differences seen for asteroids with different diameters. More work should also be done to improve the orbits when more observations of the UESAC asteroids are made available.
© European Southern Observatory (ESO) 1997
Online publication: July 8, 1998