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Planetary Classification List

The aim of the WorldGen system is to generate random worlds which are diverse, interesting and also vaguely sensible. To aid in this, a broad range of planet types have been defined. This list is based on work done by John Dollan, and his far more complete version is at the ArcBuilder Site.

The original list, plus later versions, seem to have vanished from the web. There seems to be a partial copy available at

There is also a version adapted for the Eclipse Phase RPG available as PDF by James Mephit.

This version is based on a combination of these resources, plus some further modifications.

The list is split into Groups, Classes and Types. The top level groups are:

  • Belt Group - A collection of a large number of Small Bodies. This is a meta classification to denote a belt or ring around a star or planet.
  • Small Body Group - Includes small planetoids such as asteroids or coments, generally not more than 10s of kilometres in diameter.
  • Dwarf Terrestrial Group - Small rocky dwarf planets with a mass up to 0.15 of that of Earth. They are generally spherical and may have a trace atmosphere.
  • Terrestrial Group - Rocky worlds generally from 0.02 to 5.0 Earth masses. They may have geological activity (or had it in the past) and may have a substantial atmosphere.
  • Helian Group - Rocky worlds from 3 to 17 Earth masses which lack a layer of liquid or super-condensed volatives.
  • Jovian Group - Range in mass from 10 to 4,000 times the mass of the Earth, up to 13 times the mass of Jupiter. They have rocky or icy cores, and a thick atmosphere generally of hydrogen or helium.
  • Planemo Group - Planetary mass objects which are not bound to a star. Also known as rogue planets.
  • Construct Group - Artificially constructed objects of planetary scale or larger, from orbitals thousands of kilometres across to Dyson Swarms or Matrioshka Brains.
pcl.txt · Last modified: 2018/11/24 22:55 by sam