The Last Federation:The 5 Solar System Zones
Overall there are 5 zones in the solar system, and each one has some different functionality. A lot of that functionality is expressed in terms of what kinds of planets are in each zone, and in turn what attributes those planets have, but there are some other things as well. Oh -- and this is all modeled on our own solar system, incidentally, with a few creative licenses here and there to add variety.
Very close to the sun, so very hot. This zone is able to have the following types of planets in it: Iron Silicate, Molten, and Heliosal Desert.
This is where Earth is, in our solar system. It's traditionally the most suitable area for life. This zone is able to have the following types of planets in it: Terrestrial, Over-Industrialized, and Transition Desert.
The asteroid belt does not have any planets in it. Instead, this is where asteroids lurk, the asteroid belt does not have a clear neighborhood
Out beyond the asteroid belt, you have mainly gas giants. This zone is able to have the following types of planets in it: Hypertonic Gas Giant, Gauss Gas Giant, and Equatorial Ring.
This is basically the Trans-Neptunian belt in our solar system, as well as kind of the area where Neptune itself is. The Ice Dwarf planets here are actually basically plutoids, or dwarf planets. This zone is able to have the following types of planets in it: Ice Dwarf and Dense Turbulent.
Additionally, like the asteroid belt, races will build their various space outposts here.