Orateur
Description
The asteroid proper element catalogs nowadays typically contain data
sets for more than a million asteroids, and are available from
different sources. The computation of proper elements fails in some
cases due to various dynamical or computational causes, e.g.
resonances or close approaches to perturbing planets. We assess the
significance of these cases in the overall proper elements statistics,
analysing their distribution in the phase space. Next we show some
typical examples of the failed computations, and discuss the dynamical
mechanisms giving rise to failures. The analysis confirmed that most
of the failures occur in or near strong mean motion resonances, which
pump up the eccentricities until asteroid undergoes close approaches
to the major planets, eventually ending up as a hyperbolic escapee, or
in a seriously disturbed, chaotic orbit. In addition, we consider the
existing practices of computation of synthetic proper elements,
comparing the resulting elements and frequencies, as well as their
errors, derived by using orbital integration over different time
spans, and by using an optimized choice of dynamical model in
different parts of the asteroid main belt in contrast to a more
complete model uniformly applied throughout the belt. It has been
shown that the more complex and computer time demanding approach does
not produce significant improvement and that, from the point of view
of classification of asteroids into families, proper elements computed
by means of the optimized approach can be considered as entirely
satisfactory for the classification purposes.