Planetary Classifications

Class	Description	Surface	Atmosphere
Class A	Geothermal	Partially molten	Hydrogen compounds
Class B (ex: Mercury)	Geomorteus	Partially molten, high temperature	Extremely tenuous
Class C	Geoinactive	Low temperature	Frozen
Class D (ex: Luna)	Asteroid/Moon	Barren and cratered	None or very tenuous
Class E (ex: Excalbia)	Geoplastic	Molten, high temperature	Hydrogen compounds and reactive gases
Class F	Geometallic	Volcanic	Hydrogen compounds
Class G	Geocrystalline	Crystallizing	Carbon dioxide, some toxic gases
Class H	Desert	Hot and arid, little or no water	May contain heavy gases and metal vapors
Class I	Gas Supergiant	Tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates heat	Variable presure and composition, may contain water vapor
Class J (ex: Jupiter)	Gas Giant	Tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates some heat	Variable presure and composition
Class K (ex: Mars)	Adaptable	Barren, little or no water	Thin, mostly carbon dioxide
Class L	Marginal	Rocky and barren, little water	Oxygen/Argon, high concentration of carbon dioxide
Class M (ex: Earth)	Terrestrial	Water abundant	Nitrogen, Oxygen and trace elements
Class N (ex: Venus)	Reducing	High temperature	Extreamly dense, carbon dioxide and sulfides
Class O	Palagic	80%+ water	Nitrogen, Oxygen and trace elements
Class P (ex: Breen)	Glaciated	80%+ water ice	Nitrogen, Oxygen and trace elements
Class Q (ex: Genesis Planet)	Variable	Various	Tenuous to dense
Class R	Rogue	Maybe temperate due to geothermal venting	Primarily volcanic outgassing
Class S-T	Ultragiant	Tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates considerable heat	Variable presure and composition, may contain water vapor
Class Y (ex: Tholia)	Demon	500°K+	Turbulent, saturated with toxic chemicals and therionic readiation