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• NoLWoCS is divided into three tiers of classification: Class, Type, and Subtype. The different Classes of worlds are dependent on size, overall characteristics, and status of a planet. For instance, Planetoidal and Terrestrial world Classes are divided according to size, just as Terrestrial and Jovian worlds are different Classes because of their general characteristics.

• World Types are dependant on a variety of factors, but generally the compositional elements, which often lead to different planetary features and behaviors, are of sufficient difference to separate these worlds. Subtypes are much more specific, and often are the result of what would normally be considered minor planetary features. For instance, Gaian worlds are divided into several different Subtypes based on items such as the amount of surface water, atmospheric composition, and so on.

Table of Contents

Terrestrial Worlds

Terrestrial worlds

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TERRESTRIAL CLASS: worlds with an active internal geology that lasts one million years or more: 0.05 to 2.5 x Earth's mass

• Adamaean: Carbon Worlds. Carbon-rich terrestrials. More information here
• Ferrinian: Iron-rich, dense worlds. More information here
• Hermian: Dense, inner system worlds. More information here
• Selenian: Worlds with little or no metallic core.More information here
• Cytherean: Hot, greenhouse worlds. More information here.
• PelaCytherean: Terrestrial sized hot ocean worlds with thick atmospheres. More information here.
• LithicGelidian: Worlds with a mixed rock and ice composition. More information here.
• Europan: Icy worlds with a subcrustal ocean. More information here.
• Titanian: Icy worlds with thick atmospheres. More information here.
• Ymirian: Worlds made almost entirely of ices. More information here.
• Vesperian: Tidally locked terrestrial worlds. More information here.
• Hephaestian: These are the most active of planets, with surfaces that are almost entirely molten and a geology that changes on a yearly basis. The atmospheres of these planets vary greatly according to the world's size and mass, from having thick, Cytherean-like atmospheres to almost non-existent ones, where the feeble gravity loses any elements almost as soon as they are released from the surface. These worlds are generally heated by tidal flexing, by proximity to a star or as a moon of a gas giant.
• Amunian Type: Cold, dry worlds with high levels of ammonia in addition to water. May develop an ammonia-based biosphere (see the Soft Ones xenosophonts for one example).
• Vitriolic Type: Worlds with lakes, seas or oceans of sulphuric acid; often with life, More information here.

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• Arean type: Mars-like worlds where the atmosphere and hydrosphere has largely disappeared due to the cessation of magnetic activity. .More information here.
• EoArean subtype Young Mars-like Type planet with substantial atmosphere and surface water. More information here
• AreanLacustric subtype: Young Mars-like worlds with moderate amounts of ocean cover . More information here.
• AreanXeric subtype Mature, unusually hot and dry Arean type worlds. More information here.
• AreanTundral subtype Cold Arean type worlds, often with considerable reserves of ice More information here.
• EuArean Subtype Typical mature Mars-like world with minimal atmosphere and hydrosphere More information here.

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Earth-like Worlds

• Gaian Type: Any Earth-like terrestrial world, of which there are many diverse forms depending on water content, composition and temperature. More information here
• EoGaian Subtype: Young terrestrial worlds; these may develop into Gaian, Cytherean or Arean worlds later More information here
• MesoGaian Subtype: Earth-like worlds with primitive biospheres More information here
• Eugaian Subtype A mature Gaian world with life, also known as a Garden World More Information Here
• GaianTundral Subtype: Cold Gaian worlds with periodic, or persistent, ice ages More Information Here
• Campian Subtype: Dry Gaian worlds with 25% to 50% ocean cover More Information Here
• Paludial Subtype: Humid Gaian worlds with 25% to 50% ocean cover More Information Here
• Lacustric Subtype:Humid Gaian worlds with low topography and 50-80% ocean coverage; some of these worlds have extensive rainforest-type biomes More Information Here.
• Chlorogaian (Halogenic) type: Gaian worlds with high levels of atmospheric chlorine. More: Chlorine Worlds.
• To'ul'hese Worlds: These worlds are essentially Gaian versions of the Cytherean worlds. Thick and dense atmospheres, as well as a large amount of water, create high surface pressures and high temperatures. Life arises and adapts to these conditions, and can become quite diverse indeed. In one known instance, it has lead to an independent form of sapient life. More: To'ul'hian Worlds.
• Pelagic Subtype Gaian worlds where oceans cover the surface anywhere from 80 to 100%. More Information here
• EuPelagic Subtype Gaian worlds where shallow oceans cover the surface anywhere from 80 to 100%. More information here
• BathyPelagic Subtype: Gaian worlds where deep oceans cover the surface anywhere from 80 to 100%. More information here.
• PelaGelidic Subtype, ice covered ocean worlds More information here.
• TundralPelagic subtype, partially ice covered ocean worlds More information here.
• Xeric subtype Dry worlds with less than 25% ocean cover More information here.
• HyperXeric subtype Very dry worlds with less than 10% ocean cover More information here.
• PostGaian subtype: Old Gaian Worlds that are losing their biosphere and hydrosphere More information here.

Superterrestrials

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SUPER-TERRESTRIAL CLASS: worlds that are moderately massive, intermediate in mass between Terrestrial worlds and Neptunian worlds

• Pyrothalassic Type: Hot superterrestrials More information here
• Pyrohydrothalassic Type - Hot waterworlds More information here
• Panthalassic Type: Giant Waterworlds More information here
• Nebulous Type: Superterrestrials with thick, helium-rich atmospheres. Helium worlds of this kind (generally known as Helian Worlds) often have superrotating atmospheres; those which are tidally locked often have wildly assymetric weather patterns.
• Gas Dwarfs: worlds smaller than 0.03 x the mass of Jupiter which nevertheless have thick atmospheres consisting mostly of hydrogen and helium.
• Other types of superterrestrial planets include certain hyperbarian and chthonian worlds, some of which have very sparse atmospheres indeed.

Giant Planets

Gas Giants

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In NoLWoCS, giant planets are defined as worlds which retain a thick primary atmosphere, composed of hydrogen and helium accreted from the protoplanetary disc during formation, though this atmosphere may also contain significant amounts of other gases. There are two types of giant planets:

Temperature types

• Frigidian (Frigi-): <30 K. Possible clouds of hydrogen (H2). Worlds belonging to this type are cold enough that methane condenses too deep to be visible. In absence of significant absorption in visible light by methane or any other gas, all wavelengths are scattered back by Rayleigh scattering, causing these worlds to appear white. Example: Werunos, Xiolitecek

• Cryonian (Cryo-): 30-70 K. Clouds of hydrogen sulfide (H2S) and methane (CH4), as well as organic photochemical haze. The absorption of red light by gaseous methane gives these worlds a blue colour, while photochemical haze causes them to become paler. Cryonian worlds are often lower mass planets, as massive worlds have not had time to sufficiently cool down from formation yet. Example: Uranus, Neptune, Sokramanty

• Psychronian (Psychro-): 70-200 K. Clouds of ammonium hydrosulfide (NH4SH) and ammonia (NH3), as well as organic photochemical haze. Ammonium hydrosulfide clouds can turn from white to brown when irradiated, while photochemical haze produces a beige tint. Example: Saturn, Jupiter, Amelia

• Mesonian (Meso-): 200-350 K. Clouds of water (H2O), as well as organic photochemical haze. Water clouds are white in appearance, while photochemical haze produces a beige tint, like on Psychronian worlds. Example: K2-18 b, Quijote, Guabancex

• Zestonian (Zesto-): 350-800 K. 350-800 K. Clouds of potassium chloride (KCl) between 500-800 K, as well as organic photochemical haze. Dense photochemical haze generally dominates the appearance of these worlds when present, producing a variety of colours, from brownish to reddish to greenish. Potassium chloride clouds, which form at the upper temperature range, and located deeper in the atmosphere than haze, only dominate the appearance of warmer worlds where haze formation is negligible, such as young planets or brown dwarfs in distant orbits or not bound to any star. Example: Phailinsiam, 51 Eridani b, Sakura

• Pyronian (Pyro-): 800-2100 K. Clouds of silicates, and aluminium oxide (Al2O3) and titanium dioxide (TiO2) to lesser extent, as well as strong alkali metal absorption. The alkali metal absorption produces a dark blue colour, while the clouds of silicates and metal oxides are bright and reflective. Photochemical haze is also present near the lower temperature boundary of this class. The nightside of these worlds can perceptibly glow reddish with heat. Example: Cuancoá, Dimidium, Yang

• Calidian (Cali-): >2100 K. Cloudless. The dayside of these worlds may perceptibly glow with heat, even under full sunlight. Example: WASP-33 b, KELT-9 b

Other World Classes

• HyperBarian Class: Very dense planets with cores up to 100 x Earth's mass. More information here.
• Chthonian Class: Former hot giant worlds which have lost their volatiles through evaporation. More information here.
• Stevensonian Class Planetary mass objects which are found in interstellar space. More information here.

World types distinguished by their orbital and rotational parameters

Eccentric worlds and Tilted Worlds

• Skolian Type Worlds Worlds with axial tilts greater than 45 degrees; any class of world can have Skolian characteristics. More information here
• Janusian Type Worlds Worlds in resonant orbits which regularly exchange momentum. More Information here
• Ikarian type worlds Worlds with eccentric orbits, with an eccentricity greater than 0.35. Any class of world can have an Ikarian type orbit. More Information here.

• Arean Type planet
• Artificial Planets
• Artificial Worlds
• CADRS Planetary Classification System, The
• Extended World Classification System (EWoCS)
• Gaian Type
• Superterrestrial Worlds