Planetary Class

Example

Description

Class A

Jupiter 

Class A planets (Gas Supergiants) are very large, typically 300 to 1,000 times the mass of Earth, and are their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen compounds.  High core temperatures cause them to radiate heat.

Class B

Saturn, Uranus, Neptune 

Class B planets (Gas Giants) are large, typically 10 to 100 times the mass of Earth, and are in their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen and hydrogen compounds.

Class C

Venus 

Class C planets are typically of about the mass of Earth and are in their sun's habitable zone. Due to the greenhouse effect of dense atmospheres heavy in carbon dioxide, their surfaces are very hot and water is found in vapor form, if present at all.

Class D

Epsilon Indi III 

Class D planets are typically of about the mass of Earth and are in their sun's habitable zone. They are newly formed, and their surfaces are still molten. Their atmospheres still retain many hydrogen compounds, as well as reactive gases and rock vapors. These planets will cool, becoming Class E.

Class E

Rigel III, Vega III 

Class E planets are typically about the mass of Earth and are in their sun's habitable zone. They are recently formed, and their surfaces are thin. Their atmospheres still contain some hydrogen compounds. These planets will cool further, becoming Class F.

Class F

Vega IV 

Class F planets are typically about the mass of Earth and are in their sun's habitable zone. They are younger than the Earth, and their surfaces are still crystallizing. Their atmospheres retain small amounts of toxic gases.  As these planets continue cooling they may become classes C, M or N.

Class G

Ceti Alpha V, Rigel XII, Triacus 

Class G planets are typically about the mass of Earth and are in their sun's hot zone. Their gravity allows them to retain an atmosphere of heavy gases and metal vapors, but due to strong solar radiation, their surfaces are very hot.

Class H

Alpha Centauri V 

Class H planets are small, typically 1 to 1/10 the mass of Earth, and are in their sun's cold zone. They are newly formed and their surfaces are still molten. Their atmospheres still retain many hydrogen compounds, as well as reactive gases and rock vapors. These planets will cool, becoming Class L.

Class I

Luna 

Class I planets are small, typically 1 to 1/100 the mass of Earth, or less. Due to low gravity, they have lost their atmospheres. Their surfaces, directly exposed to radiation and meteor impact, are typically lifeless and heavily cratered.

Class J

Marcury 

Class J planets are small, typically 1/10 the mass of Earth, and are in their sun's hot zone. Due to a combination of weak gravity and strong solar radiation, their atmospheres are very tenuous, with few chemically active gases, and their surfaces are extremely hot.

Class K

Mars 

Class K planets are small, typically 1/10 the mass of Earth, and are in their sun's habitable zone. Due to weak gravity, their atmospheres are tenuous, but water is usually present.

Class L

Pluto 

Class L planets are small, typically 1 to 1/10 the mass of Earth and are in their sun's cold zone. Due to a combination of low solar radiation and little heat, their atmospheres are permanently frozen.

Class M

Earth, Andor, Risa, Vulcan 

Class M planets are typically about the mass of Earth and are in their sun's habitable zone. Their atmospheres contain significant oxygen, liquid water is a significant surface feature, and lifeforms are generally abundant. With more water they would be class N.

Class N

Argo, Deneb III 

Class N planets are typically about the mass of the Earth and are in their sun's habitable zone. Their atmospheres contain significant oxygen, liquid water covers over 97 percent of the surface. Lifeforms are generally abundant. With less water they would be Class M.

Class S

Delta VI, Delta X, Morphus 

Class S planets (Gas Ultragiants) are very large, typically 10,000 times the mass of Earth, and are in their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen and hydrogen compounds. High core temperatures cause them to radiate visible light. These are the largest possible planets, as more massive bodies generate enough core heat to initiate fusion reactions and become stars.

Class T

Bruedon Epsilon V Optima Alpha V 

Class T planets (Gas Supergiants) are very large, typically 3,000 times the mass of the Earth, and are in their sun's cold zone. Low solar radiation and high gravity have allowed them to keep thick atmospheres of hydrogen and hydrogen compound. High core temperatures cause them to radiate enough heat that liquid water is present.

Class Y

Demon

Class Y planets are typically about the mass of earth and are in their sun's habitable zone. Their gravity's are about Earth's. Their atmospheres are full of toxic gases, radiation. Their atmospheres relese spikes of Thermionic (ther-me-on-ick) radiation. The tempature on the planet is over 500 Kelvins.