Astronomers are now faced with increasing numbers of apparently unusual planetary systems, and simulation models are being developed to explain these giant planets around Sun-like stars. The systems that have been discovered are heavily biased by the methods used to detect them, with the bias towards planets at least as large as Jupiter and relatively near their stars, but the observations have provided evidence of the apparent diversity of solar systems.
Simulation models produce a wide variety of final planetary systems.
Another cause of the variety of simulation results is that the models involve a highly chaotic dynamical evolution of a small number of planetary embryos, and this results in variable locations and numbers of planets. Stable systems, for example, have been found to range from 1 to 7 planets. Thus it is unreasonable to demand that planet-formation theories produce our own Solar System in detail. Twenty-Eight ways to build a solar system. As the mass of the agglomerate increases, so does the rate of accretion, and this accretion process is believed to generally occur in the form of a disk.