Planetary Classifications

08/16/2006: The following information does not directly correspond to that in "Star Trek Star Charts". I will be reviewing the differences, and updating as needed at some point, soon hopefuly.

Class A - Gas Supergiant
Planets of this class are usually found in a star's outer or "cold zone." They are typically 140,000 to 10,000,000 kilometers in diameter and have high core temperatures causing them to radiate heat. Low stellar radiation and high planet gravity enable them to keep a tenuous surface comprised of gaseous hydrogen and hydrogen compounds.

Examples: Alpha 4 & 5, Antares 4 & 5, Antos 5, Arcturus 5, Argelius 5, Betelgeuse 3, Canopus 6, Eminiar 10, Herculis 3, Jupiter (Sol 5), Rigel 13, Spica 1 & 2, UFC 892 10 & 11, Vega 5 & 6.

Class B - Gas Giant
Class B Planets are usually found in a star's outer or "cold zone." They are typically 50,000 to 140,000 kilometers in diameter and have high core temperatures but do not radiate much heat. Low stellar radiation and high planet gravity enable them to keep a tenuous surface comprised of gaseous hydrogen and hydrogen compounds.

Examples: 61 Cygni 7, Alpha Centauri 6, Arcturus 6 & 7, Argelius 6 & 7, Betelgeuse 4 & 5, Canopus 7, Epsilon Bootis 4, Epsilon Indi 7 & 9, Neptune (Sol 8), Procyon 5, Rigel 10, 11 & 14, Saturn (Sol 6), Uranus (Sol 7)

Class C - Reducing
Planets of this class are usually found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter. They have high surface temperatures due to the "greenhouse effect" caused by their dense atmospheres. The only water found is in vapor form.

Examples: 61 Cygni 2 & 3, Alpha Tauri 2, Arcturus 2, Argelius 1, Epsilon Indi 2, Medusa, Rigel 1, Sirius 2, Tau Ceti 2, Tholia, Venus (Sol 2).

Class D - Geo-Plastic
Planets of this class are usually found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter. They have a molten surface because they have been recently formed. The atmosphere contains many hydrogen compounds and reactive gases. Class D planets eventually cool, becoming class E.

Examples: Epsilon Indi 3, Excalbia

Class E - Geo-Metallic
Planets of this class have a molten core and are usually found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter. Their atmospheres still contain hydrogen compounds. They will cool further eventually becoming class F.

Examples: 61 Cygni 4, Altair 3, Arcturus 3, Capella 3, Canopus 4, Janus 6, Rigel 3, Vega 3

Class F - Geo-Crystalline
Class F planets are usually found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter and have surfaces that are still crystalizing. Their atmospheres still contain some toxic gases. They will cool eventually, becoming class C, M or N.

Examples: Delta Vega 2, Vega 4

Class G - Desert
Planets of this class can be found in any of a star's zones. They are typically 8,000 to 15,000 kilometers in diameter. Their surfaces are usually hot. Their atmospheres contain heavy gases and metal vapors.

Examples: Capella 4, Ceti Alpha 5, Rigel 12, Tau Ceti 5, Taurus 2, Triacus (Epsilon Indi 4)

Class H - Geo-Thermal
Planets of this class are usually found in a star's "habitable zone" or "cold zone." They are typically 1,000 to 10,000 kilometers in diameter. They have partially molten surfaces and atmospheres that contain many hydrogen compounds. They cool, becoming class L.

Examples: Alpha Centauri 5, Gothos, T'khut (40 Eridani 2)

Class I - Asteroid/Moon
Planetary bodies of this class can be found in any of a star's zones. They are usually found in orbit of larger planets or in asteroid fields. They are typically 100 to 1,000 kilometers in diameter. They have no atmospheres. Their surfaces are barren and cratered.

Examples: Ceres, Deimos, Kera, Luna, Phinda, Phobos

Class J - Geo-Morteus
Planets of this class are found in a star's "hot zone". They are typically 1,000 to 10,000 kilometers in diameter. They have high surface temperatures due to the proximty to the star. Their atmospheres are extremely tenuous with few chemically active gases.

Examples: Alpha Centauri 1, Alpha Tauri 1, Altair 1 & 2, Arcturus 1, Canopus 1, Capella 1 & 2, Deneb 1, Mercury (Sol 1), Procyon 1 & 2, Sirius 1, Vega 1 & 2

Class K - Adaptable
Planets of this class are usually found in a star's "habitable zone." They are adaptable for humanoid colonization through the use of pressure domes and other life support devices. They are typically 5,000 to 10,000 kilometers in diameter. They have thin atmospheres. Small amounts of water are present.

Examples: Alpha Centauri 2 & 3, Alpha Taur 4, Altair 6, Antares 2 & 3, Argelius 3 & 4, Betelgeuse 2, Canopus 5, Mars (Sol 4), Mudd Procyon 4, Rigel 9, Sirius 4, Vega 7 & 8, Velara 3

Class L - Geo-Inactive
Planets of this class are usually found in a star's "habitable zone" or "cold zone." They are typically 1,000 to 10,000 kilometers in diameter. Low solar radiation and minimal internal heat usually result in a frozen atmosphere.

Examples: Alpha 3, Antares B 3, Aurelia, Epsilon Indi 10, Marcos 12, Orna, Pluto (Sol 9), Psi-2000, Sauria, Sirius 8 & 9, Time Planet

Class M - Terrestrial
Planets of this class are found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter. They have atmospheres that contain oxygen and nitrogen. Water and life-forms are typically abundant. If water covers more than 97% of the surface, then they are considered class N.

Examples: Alpha Centauri 7, Andor (Epsilon Indi 8), Aldebaran (Alpha Tauri 3), Antos 4, Arcturus 4, Argelius 2, Benzar, Betazed, Betelgeuse 1, Bynaus, Cait, Canopus 2 & 3, Cardassia, Catulla, Daran 5, Delta 5, Deneb 2, 4 & 5, Earth (Sol 3), Melkotia, Merak 2, Phylos 2, Qo'noS, Rigel 2, 4 & 8, Risa, Spica 3, Tellar (61 Cygni 5), Tiburon, Vega 9

Class N - Pelagic
Class N planets are usually found in a star's "habitable zone." They are typically 10,000 to 15,000 kilometers in diameter. They have atmospheres that contain oxygen and nitrogen . Water and life-forms are typically abundant. If water covers less than 97% of the surface, then they are considered class M.

Examples: Argo, Ascella, Canopus 8, Deneb 3

Class S - Near Star
Planets of this class are usually found in a star's "cold zone." They are typically 50,000,000 to 120,000,000 kilometers in diameter and have high core temperatures causing them to radiate heat and light. These are the largest possible planets, because most planetary bodies that reach this size do become stars.

Examples: Bader Beta 10, Bruedon Beta 4, Horst 10, M'kyru Epsilon 4, Morphus Delta 10, Pandemus Epsilon 5, Ruhr Beta 6, Rydle Delta 7, Shonoisho Delta 6

Class T - Gas Ultragiant
Planets of this class are usually found in a star's "cold zone." They are typically 10,000,000 to 50,000,000 kilometers in diameter. They have high core temperatures causing them to radiate enough heat to keep water in a liquid state.

Examples: Bruedon Epsilon 5, Optima Alpha 5

CLASS Y - Demon
Planets and planetoids of this class can be found in any of a star's zones. They are typically 10,000 to 15,000 kilometers in diameter. Atmospheric conditions are often turbulent and saturated with poisonous chemicals and thermionic radiation. Surface temperatures can reach in excess of 500 K. (Starfleet Note: Communication is frequently impossible, and transport may be difficult. Simply entering orbit is a dangerous prospect. No known environment is less hospitable to humanoid life than a Class Y planetary body.)

This information from MJ's Star Trek site