Protostellar Disks and Planet Formation

The planets in the solar system are for the most part in near circular orbits which approximately lie in the same plane. The hypothesis that they were formed in a flattened differentially rotating gaseous disc was originally proposed by Laplace (1796) to account for the origin of these dynamical properties and it has been the subject of much theoretical development in recent times (e.g. Lin and Papaloizou, 1985, 1993 and references therein).