SFAC - Planetary Classification Guide

Class M

• Age: 3-10 billion years
• Diameter: 10,000 - 15,000 km
• Location: Ecosphere
• Surface: Surface water abundant; if water or ice covers more than 80% of surface, planet is considered Class-O or Class-P
• Atmosphere: Nitrogen, oxygen, trace elements
• Life-Forms Extensive vegetation, animal life, humanoids
• Example: Earth, Vulcan, Cardassia Prime

Class M planets range in age from 3 to 10 billion years old. Their diameters range in size from 10,000 to 15,000 km. They are always located in the ecozone region of a star's solar system. Their surfaces are comprised with a relatively thin tectonic layer floating on a molten rock mantle, usually with active volcanoes present. Class M planets have an abundant amount of water necessary for life to exist. Their atmospheres contain oxygen/nitrogen with other trace gases. Life forms are almost always present, flourishing as extensive plant and animal life. Usually a sentient race is also present.

Class M planets are also called Minshara Class, a Vulcan term.

Planets with more than 80% surface water fall under Class O or Class P.

[edit] Class N: Reducing

Class N Age: 3-10 billions 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 N planets range in age from 3 to 10 billion years old. Their diameters range in size from 10,000 to 15,000 km. They are usually located in the ecozone region of a star's solar system. Class N worlds are barren and rocky. Their surfaces temperatures are usually high due to an intense greenhouse effect. Water exists, but only as vapor. They have extremely dense atmospheres containing carbon dioxide and sulfides. Life forms, if any, would have to be adapted to such an extremely harsh environment. There may be single-celled organisms living in the upper layers of atmosphere. [edit] Class O: Pelagic Class O 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 O planets range in age from 3 to 10 billion years old. Their diameters range in size from 10,000 to 15,000 km. They are always located in the ecozone region of a star's solar system. Class O worlds have an extreme abundance of water covering more than 80% of their surface. They have Class M-like atmospheres, with oxygen/nitrogen and other trace elements. There is almost always life, but almost all of it is aquatic plant and animal life, with little land mass to evolve surface creatures. Sentient races evolving on such worlds are likely to be aquatic in nature. [edit] Class P: Glaciated Class P 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, Breen Homeworld Class P planets range in age from 3 to 10 billion years old. Their diameters range in size from 10,000 to 15,000 km. They are usually located on the extreme edge of the ecozone region of a star's solar system. Class P worlds have an extreme abundance of water, but much of it is frozen in ice, covering more than 80% of the surface. They have Class M-like atmospheres, with oxygen, nitrogen, and other trace elements. There is usually hardy plant and animal life surviving in the tundra. [edit] Class Q: Variable Class Q Age: 2-10 billion years Diameter: 4,000 - 15,000 km Location: Hot Zone / Ecosphere / Cold Zone Surface: Ranges from molten to water and/or carbon dioxide ice, due to eccentric orbit or variable output of star Atmosphere: Ranges from tenuous to very dense Example: Genesis Planet The environment of a Class Q fluctuates because they orbit a variable output star. These planets range in age from 2 to 10 billion years old. Their diameters range in size from 4,000 to 15,000 km. They are usually located in the hotzone or ecozone regions of a star's solar system. Surfaces range from molten rock to water and/or carbon dioxide ice due to the variable output of the star they orbit. Their atmospheres range from tenuous to extremely dense. Life, if any, would have to rapidly adapt to sudden changes in temperatures. [edit] Class R: Rogue Class R Age: 2-10 billion years Diameter: 4,000 - 15,000 km Location: Interstellar space, cometary halos Surface: May be temperate due to geothermal venting Atmosphere: Primarily volcanic outgassing Life-Forms: Non-photosynthetic plants, animal life Example: Dakala Class R rogue planets do not orbit stars. They range in age from 2 to 10 billion years old. Their diameters range in size from 4,000 to 15,000 km. Surfaces are usually barren, but some might be temperate due to geothermal venting. Atmospheres tend to be filled with volcanic outgassing. They are not believed to support life, but some might have animal and non-photosynthetic plant life. [edit] Class S and T: Ultragiants (Near Star) Class S & T Age: 2-10 billion years Diameter: 10-50 million km (Class-S) / 50-120 million km (Class-T) Location: Cold Zone Surface: Tenuous, composed of gaseous hydrogen and hydrogen compounds; radiates considerable heat Atmosphere: Zones vary in termperature, pressure and composition; water vapor may be present Life-Forms: Unknown Class S and Class T planets are super gas giants. They range in age from 2 to 10 billion years old. Their diameters range in size from 10 to 50 million km (Class S) and 50 to 120 million km (Class T). They are usually located in a solar system's coldzone, but they can be in any region. Their surface is tenuous, composed of hydrogen and helium compounds. They radiate considerable heat and tremendous gravity. The atmosphere varies in temperature, pressure and composition at different layers. There may also be water vapor present. Life forms may only exist as single-celled organisms if any exist at all. They may have hundreds or thousands of moons, some of which may be terrestrial planets of Class M, O and P. [edit] Class Y: Demon Class Y Age: 2-10 billion years Diameter: 10,000 - 50,000 km Location: Hot Zone / Ecosphere / Cold Zone Surface: Temperatures can exceed 500°K Atmosphere: Turbulent, saturated with toxic chemicals and thermionic radiation Life-Forms: Mimetic (Delta Quadrant) Class Y is reserved for planets referred to as "Demon" worlds. They are usually hostile to humanoid life because they contain turbulent, sometimes volcanic environments with atmospheres filled with toxic and corrosive gasses. They range from 10,000 to 50,000 km in diameter, and can reside in any region of a star's solar system. They generate thermionic radiation, and exhibit very high surface temperatures. Life forms, if any, will probably be silicon-based or mimetic in nature, as experienced on Demon class worlds of the Delta Quadrant.