So the Kuiper belt seems to be a good candidate for a cometary storehouse. And the mechanics of the transfer out of storage is now well understood. Ultimately, many of these small bodies slowly burn up as comets. Others will be caught in a gravitational slingshot that ejects them into the far reaches of interstellar space. The answer may lie in the Centaurs, a group of objects that includes the extremely red 5145 Pholus.
Centaurs travel in huge planet-crossing orbits that are fundamentally unstable.
They can remain among the giant planets for only a few million years before gravitational interactions either send them out of the solar system or transfer them into tighter orbits. With orbital lifetimes that are far shorter than the age of the solar system, the Centaurs could not have formed where they currently are found. Yet the nature of their orbits makes it practically impossible to deduce their place of origin with certainty. The strongest evidence supporting this hypothesis comes from one particular Centaur-2060 Chiron . As astronomers continue to study the Kuiper belt, some have started to wonder whether this reservoir might have yielded more than just comets.