Star Charts · Chapter 3 · Planets
3.0 Planetary Classes A–C (Geothermal, Geomorteus, Geoinactive)
Reference data for planetary classes A, B and C, listing age, diameter, location, surface, atmosphere, evolution, life-forms and an example for each.
Class A Geothermal planet, a partially molten orange-red world.
Class B Geomorteus planet, a dark cratered world resembling Mercury.
Class C Geoinactive planet, a frozen grey cratered world.
Class A — Geothermal
- Age: 0-2 billion years
- Diameter: 1,000-10,000 km
- Location: Ecosphere/Cold Zone
- Surface: Partially molten
- Atmosphere: Primarily hydrogen compounds
- Evolution: Cools to become Class-C
- Life-forms: None
- Example: Gothos
Class B — Geomorteus
- Age: 0-10 billion years
- Diameter: 1,000-10,000 km
- Location: Hot Zone
- Surface: Partially molten, high surface temperature
- Atmosphere: Extremely tenuous, few chemically active gases
- Life-forms: None
- Example: Mercury
Class C — Geoinactive
- Age: 2-10 billion years
- Diameter: 1,000-10,000 km
- Location: Ecosphere/Cold Zone
- Surface: Low surface temperature
- Atmosphere: Frozen
- Life-forms: None
- Examples: Pluto, Psi 2000