A new class of trans-Neptunian objects in high-eccentricity orbits

A symplectic integrator is used to study the evolution of high-eccentricity trans-Neptunian objects (TNOs) over the age of the Solar system. For 26 objects, a few cloned orbits were integrated. We demonstrate the existence of several known bodies that are in relatively stable orbits located far from Neptune for the age of the Solar system. Thus, we provide an indication of the structure of the protoplanetary disc immediately after the period of planet formation. The orbits of these bodies cannot be explained by a model in which a near-Neptune disc of planetesimals is gravitationally scattered by Neptune. In this paper, therefore, we demonstrate the existence of a new, and populous, class of 'outer' TNOs which have substantially different dynamical characteristics from those of scattered disc objects.