Star Charts · Chapter 3 · Planets
3.5 Planetary Classes N–P (Reducing, Pelagic, Glaciated)
Reference data for planetary classes N, O and P, listing age, diameter, location, surface, atmosphere, life-forms and an example for each.
Class N Reducing planet, a dense pale-yellow greenhouse world resembling Venus.
Class O Pelagic planet, a blue ocean world with white clouds.
Class P Glaciated planet, a white ice-covered world.
Class N — Reducing
- Age: 3-10 billion years
- Diameter: 10,000-15,000 km
- Location: Ecosphere
- Surface: High surface temperature due to greenhouse effect; water exists only as vapor
- Atmosphere: Extremely dense, carbon dioxide and sulfides
- Life-forms: Unknown
- Example: Venus
Class O — Pelagic
- Age: 3-10 billion years
- Diameter: 10,000-15,000 km
- Location: Ecosphere
- Surface: Liquid water covers 80% or more of surface area
- Atmosphere: Nitrogen, oxygen, trace elements
- Life-forms: Aquatic vegetation, animal life, humanoids
- Example: Argo
Class P — Glaciated
- Age: 3-10 billion years
- Diameter: 10,000-15,000 km
- Location: Ecosphere
- Surface: Water ice covers 80% or more of surface area
- Atmosphere: Nitrogen, oxygen, trace elements
- Life-forms: Hardy vegetation, animal life, humanoids
- Example: Exo III