Planetary Classification

From Star Trek: Theurgy Wiki

A planet is a celestial body in orbit around a star or stellar remnants, that has sufficient mass for self-gravity and is nearly spherical in shape. A planet must not share its orbital region with other bodies of significant size (except for its own satellites), and must be below the threshold for thermonuclear fusion of deuterium.

If a celestial body meets those requirements, it is considered a planet; at that point, the planet is further classified by its atmosphere and surface conditions into one of twenty-two categories.

Contents

Class A - Geothermal Class G - Geocrystalline Class M - Terrestrial Class S - Gas Supergiant
Class B - Geomorteus Class H - Desert Class N - Reducing Class U - Gas Ultragiant
Class C - Geoinactive Class I - Ice Giant (Uranian) Class O - Pelagic Class X - Chthonian
Class D - Dwarf Class J - Gas Giant (Jovian) Class P - Glaciated Class Y - Demon
Class E - Geoplastic Class K - Adaptable Class Q - Variable
Class F - Geometallic Class L - Marginal Class R - Rogue


Class A - Geothermal

Class A planets are very small, barren worlds rife with volcanic activity. This activity traps carbon dioxide in the atmosphere and keeps temperatures on Class A planets very hot, no matter the location in a star system. When the volcanic activity ceases, the planet "dies" and is then considered a Class C planet.

AGE 0-2 billion years ClassA3.png
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SURFACE Partially molten, very hot
ATMOSPHERE Carbon dioxide, hydrogen
EVOLUTION Cools to become Class C
LIFE FORMS None
EXAMPLES Gothos

Class B - Geomorteus

Class B planets are generally small worlds located within a star system's Hot Zone. Highly unsuited for humanoid life, Class B planets have thin atmospheres composed primarily of helium and sodium. The surface is molten and highly unstable; temperatures range from 450° in the daylight, to nearly -200° at night. No life forms have ever been observed on Class B planetoids.

AGE 0-10 billion years ClassB3.png
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone
SURFACE Partially molten
ATMOSPHERE Exremely Tenuous
EVOLUTION N/A
LIFE FORMS None
EXAMPLES Mercury, Nebhilum

Class C - Geoinactive

When all volcanic activity on a Class A planet ceases, it is considered Class C. Essentially dead, these small worlds have cold, barren surfaces and possess no geological activity.

AGE 2-10 billion years ClassC3.png
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SURFACE Barren
ATMOSPHERE None
EVOLUTION N/A
LIFE FORMS None
EXAMPLES Psi 2000

Class D - Dwarf

Also known as Plutonian objects, these tiny worlds are composed primarily of ice and are generally not considered true planets. Many moons and asteroids are considered Class D, as are the larger objects in a star system's Kuiper Belt. Most are not suitable for humanoid life, though many can be colonized via pressure domes.

AGE 2-10 billion years ClassD3.png
DIAMETER 100 - 4,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SURFACE Barren, Cratered
ATMOSPHERE None or Very Tenuous
EVOLUTION N/A
LIFE FORMS None
EXAMPLES Pluto, Ceres, Eredas-Il

Class E - Geoplastic

Class E planets represent the earliest stage in the evolution of a habitable planet. The core and crust is completely molten, making the planets susceptible to solar winds and radiation and subject to extremely high surface temperatures. The atmosphere is very thin, composed of hydrogen and helium. As the surface cools, the core and crust begin to harden, and the planet evolves into a Class F world.

AGE 2-10 billion years ClassE3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Molten, high surface temp.
ATMOSPHERE Hydrogen compounds
EVOLUTION Cools to become Class F
LIFE FORMS Carbon cycle
EXAMPLES Excalbia

Class F - Geometallic

A Class E planet makes the transition to Class F once the crust and core have begun to harden. Volcanic activity is also commonplace on Class F worlds; the steam expelled from volcanic eruptions eventually condenses into water, giving rise to shallow seas in which simple bacteria thrive. When the planet's core is sufficiently cool, the volcanic activity ceases and the planet is considered Class G.

AGE 1-3 billion years ClassF3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Volcanic, barren
ATMOSPHERE Carbon dioxide, ammonia, methane
EVOLUTION Cools to become Class G
LIFE FORMS Bacteria
EXAMPLES Janus IV

Class G - Geocrystalline

After the core of a Class F planet is sufficiently cool, volcanic activity lessens and the planet is considered Class G. Oxygen and nitrogen are present in some abundance in the atmosphere, giving rise to increasingly complex organisms such as primitive vegetation like algae, and animals similar to sponges and jellyfish. As the surface cools, a Class G planet can evolve into a Class H, K, L, M, N, O, or P class world.

AGE 3-4 billion years ClassG3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Rocky, mostly barren
ATMOSPHERE Carbon dioxide, oxygen, nitrogen
EVOLUTION Cools to Class H, K, L, M, N O, P
LIFE FORMS Vegetation, simple organisms
EXAMPLES Delta Vega

Class H - Desert

A planet is considered Class H if less than 20% of its surface is water. Though many Class H worlds are covered in sand, it is not required to be considered a desert; it must, however, receive little in the way of precipitation. Drought-resistant plants and animals are common on Class H worlds, and many are inhabited by humanoid populations. Most Class H worlds are hot and arid, but conditions can vary greatly.

AGE 4-10 billion years ClassH3.png
DIAMETER 8,000 - 15,000 km
LOCATION Ecosphere
SURFACE Hot, arid; >20% surface water
ATMOSPHERE Oxygen, nitrogen, argon, metals
EVOLUTION n/a
LIFE FORMS Drought-resistant plants/animals
EXAMPLES Nimbus III, Ocampa

Class I - Ice Giant (Uranian)

Also known as Uranian planets, these gaseous giants have vastly different compositions from other giant worlds; the core is mostly rock and ice surrounded by a tenuous layers of methane, water, and ammonia. Additionally, the magnetic field is sharply inclined to the axis of rotation. Class I planets typically form on the fringe of a star system.

AGE 2-10 billion years ClassI3.png
DIAMETER 30,000 - 100,000 km
LOCATION Cold Zone
SURFACE Rock, ice, methane, ammonia
ATMOSPHERE Hydrogen, Helium
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Uranus, Neptune, Q'tahL

Class J - Gas Giant (Jovian)

Class J planets are massive spheres of liquid and gaseous hydrogen, with small cores of metallic hydrogen. Their atmospheres are extremely turbulent, with wind speeds in the most severe storms reaching 600 kph. Many Class J planets also possess impressive ring systems, composed primarily of rock, dust, and ice. They form in the Cold Zone of a star system, though typically much closer than Class I planets.

AGE 2-10 billion years ClassJ3.png
DIAMETER 50,000 - 500,000 km
LOCATION Cold Zone
SURFACE Liquid metallic Hydrogen
ATMOSPHERE Hydrogen, Helium
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Jupiter, Saturn

Class K - Adaptable

Though similar in appearance to Class H worlds, Class K planets lack the robust atmosphere of their desert counterparts. Though rare, primitive single-celled organisms have been known to exist, though more complex life never evolves. Humanoid colonization is, however, possible through the use of pressure domes and in some cases, terraforming.

AGE 4-10 billion years ClassK3.png
DIAMETER 5,000 - 10,000 km
LOCATION Ecosphere
SURFACE Barren, little surface water
ATMOSPHERE Thin, mostly carbon dioxide
EVOLUTION n/a
LIFE FORMS Primitive single-cell organisms
EXAMPLES Mars, Mudd

Class L - Marginal

Class L planets are typically rocky, forested worlds devoid of animal life. They are, however, well-suited for humanoid colonization and are prime candidates for terraforming. Water is typically scarce, and if less than 20% of the surface is covered in water, the planet is considered Class H.

AGE 4-10 billion years ClassL3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Rocky, little surface water
ATMOSPHERE Argon, oxygen, trace elements
EVOLUTION n/a
LIFE FORMS Limited to vegetation
EXAMPLES Alarin III, Ciden II, Indri VII

Class M - Terrestrial

Class M planets are robust and varied worlds composed primarily of silicate rocks, and are highly suited for humanoid life. To be considered Class M, between 20% and 80% of the surface must be covered in water; it must have a breathable oxygen-nitrogen atmosphere and temperate climate.

AGE 4-10 billion years ClassM3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Abundant surface water, temperate climate
ATMOSPHERE Nitrogen, oxygen, argon
EVOLUTION n/a
LIFE FORMS Vegetation, animal, & humanoid
EXAMPLES Earth, Cardassia, Bajor, Vulcan

Class N - Reducing

Though frequently found in the Ecosphere, Class N planets are not conducive to life. The terrain is barren, with surface temperatures in excess of 500° and an atmospheric pressure more than 90 times that of a Class-M world. Additionally, the atmosphere is very dense and composed of carbon dioxide; water exists only in the form of thick,vaporous clouds that shroud most of the planet.

AGE 3-10 billion years ClassN3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE Barren, high temps.
ATMOSPHERE carbon dioxide and sulfides
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Venus

Class O - Pelagic

Any planet with more than 80% of the surface covered in water is considered Class O. These worlds are usually very warm and possess vast cetacean populations in addition to tropical vegetation and animal life. Though rare, humanoid populations have also formed on Class O planets.

AGE 3-10 billion years ClassO3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE 80% water, archipelagos
ATMOSPHERE Nitrogen, oxygen, argon
EVOLUTION n/a
LIFE FORMS Cetacean, humanoid, animal
EXAMPLES Azati Prime, Ka'Tula Prime, Zirat

Class P - Glaciated

Any planet whose surface is more than 80% frozen is considered Class P. These glaciated worlds are typically very cold, with temperatures rarely exceeding the freezing point. Though not prime conditions for life, hearty plants and animals are not uncommon, and some species, such as the Aenar and the Andorians, have evolved on Class P worlds.

AGE 3-10 billion years ClassP3.png
DIAMETER 10,000 - 15,000 km
LOCATION Ecosphere
SURFACE 80% frozen water, cold
ATMOSPHERE Nitrogen, oxygen
EVOLUTION n/a
LIFE FORMS Vegitation, Animal, Humanoid
EXAMPLES Andoria, Rura Penthe

Class Q - Variable

These rare planetoids typically develop with a highly eccentric orbit, or near stars with a variable output. As such, conditions on the planet's surface are widely varied. Deserts and rain forests exist within a few kilometers of each other, while glaciers can simultaneously lie very near the equator. Given the constant instability, is virtually impossible for life to exist on Class-Q worlds

AGE 2-10 billion years ClassQ3.png
DIAMETER 4,000 - 15,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SURFACE Molten, frozen, jungle, etc
ATMOSPHERE Very tenuous to very dense
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Genesis Planet

Class R - Rogue

A Class R planet usually forms within a star system, but at some point in its evolution, the planet is expelled, likely the result of a catastrophic asteroid impact. The shift radically changes the planet's evolution; many planets merely die, but geologically active planets can sustain a habitable surface via volcanic outgassing and geothermal venting.

AGE 2-10 billion years ClassR3.png
DIAMETER 4,000 - 15,000 km
LOCATION Interstellar Space
SURFACE Temperate
ATMOSPHERE Primarily Volcanic Outgassing
EVOLUTION n/a
LIFE FORMS Non-photosynthetic plants, animals
EXAMPLES Founders' Homeworld (prior to 2371)

Class S - Gas Supergiant

Aside from their immense size, Class S planets are very similar to their Class J counterparts, with liquid metallic hydrogen cores surrounded by a hydrogen and helium atmosphere.

AGE 2-10 billion years ClassS3.png
DIAMETER 500,000 - 100,000,000 km
LOCATION Cold Zone
SURFACE Liquid metallic hydrogen
ATMOSPHERE Hydrogen and helium
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Tethe-Alla IV

Class U - Gas Ultragiant

Class U planets represent the upper limits of planetary masses. Most exist within a star system's Cold Zone and are very similar to Class S and J planets. If they are sufficiently massive (13 times more massive than Jupiter), deuterium ignites nuclear fusion within the core, and the planet becomes a red dwarf star, creating a binary star system.

AGE 2-10 billion years ClassU3.png
DIAMETER 50,000,000 - 120,000,000 km
LOCATION Cold Zone
SURFACE Liquid hydrogen, deuterium
ATMOSPHERE Hydrogen and helium
EVOLUTION Can evolve into red dwarf stars
LIFE FORMS None
EXAMPLES Diadem, Tethe-Alla V

Class X - Chthonian

Class X planets are the result of a failed Class T planet in a star system's Hot Zone. Instead of becoming a gas giant or red dwarf star, a Class X planet was stripped of its hydrogen/helium atmosphere. The result is a small, barren world similar to a Class B planet, but with no atmosphere and an extremely dense, metal-rich core.

AGE 2-10 billion years ClassX3.png
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone
SURFACE Barren, extremely hot
ATMOSPHERE None
EVOLUTION n/a
LIFE FORMS None
EXAMPLES Osirus

Class Y - Demon

Perhaps the most environmentally unfriendly planets in the galaxy, Class Y planets are toxic to life in every way imaginable. The atmosphere is saturated with toxic radiation, temperatures are extreme, and atmospheric storms are amongst the most severe in the galaxy, with winds in excess of 500 kph.

AGE 2-10 billion years ClassY3.png
DIAMETER 10,000 - 15,000 km
LOCATION Hot Zone
SURFACE Barren, extremely hot
ATMOSPHERE Turbulent, with toxic radiation
EVOLUTION n/a
LIFE FORMS Mimetic
EXAMPLES Planet Hell (Delta Quadrant), Visalayan (Medusan)

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