The Dynamical Structure of the Kuiper Belt and Its Primordial Origin

Since its discovery in 1992, the Kuiper belt has slowly revealed a stunningly complex dynamical structure. This structure has been a gold mine for those of us interested in planet formation because it provides vital clues about this process. This chapter is a review of the current state of knowledge about these issues. It is divided in two parts. The first part (section 2) is devoted to the description of the current dynamics in the Kuiper belt. This will be used in section 3 to highlight the properties of the Kuiper belt population that cannot be explained by the current dynamical processes, but need to be understood in the framework of a scenario of primordial evolution of the outer Solar System. In the second part, we will review the models that have been proposed so far to explain the various puzzling properties of the Kuiper belt. More precisely, section 4 will focus on the origin of the outer edge of the belt; section 5 will describe the effects of the migration of Neptune on the orbital structure of the Kuiper belt objects (KBOs) and section 6 will discuss the origin of the mass deficit of trans-Neptunian population. In section 7 we will present the consequences on the Kuiper belt of a model of the outer Solar System evolution that has been recently proposed to explain the orbital architecture of the planets, the Trojan populations of both Jupiter and Neptune, and the origin of the Late Heavy Bombardment of the terrestrial planets. A general discussion on the current state-of-the-art in Kuiper belt modelling will close the paper in section 8.