Trans-neptunian objects

Since the periodicity of comets was first established by Halley, the question of their origin has fascinated astronomers. It is clear that they have to be stored somewhere, since their life time in the inner Solar System is short. Around 1950 the idea emerged that cometary nuclei could be stored in a belt beyond Neptune, and this belt became known as the Kuiper Belt or perhaps more fairly the Kuiper-Edgeworth Belt. In the late 80’s optical searches for the belt became numerous and in 1992, the first detection (of 1992 QB1) was made. At the time of writing 39 objects have been discovered and the current state of knowledge regarding these “Kuiper-Edgeworth Belt”, or Trans-Neptunian, Objects is reviewed here.