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Non-luminary World Classifications

The Non-Luminary World Classification Scheme, or NoLWoCS, is a near standard classification method used to identify the many different forms of planetary bodies, minor worlds, and artificial structures that have evolved naturally or that have been created by the many societies and cultures of the Terragen Sphere.  While every world or megastructure is, in its own way, unique, there are certain characteristics that can be used to identify and classify these places.  The purpose of NoLWoCS is to provide an easy, "at a glance" platform for the common User, whereby he might find the navigation of the Sphere, virtual or real, a little easier.

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.  And, of course, artificial worlds are different from all of these because they are not naturally occurring.

World Types are dependants 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.

ASTEROID CLASS – non-spherical worlds of extremely low mass

Asteroidal Class The Asteroidal Class is the most basic, and the most numerous, of all the classes in the NoLWoCS.  There are, of course, even more numerous smaller objects, namely meteoroids and space dust, and these are the ultimate building blocks of any solar system.  But only asteroids can be considered worlds in their own right.  By NoLWoCS definition, these are worlds from 50 meters to 50 kilometers in diameter.  They include the classically separate rocky asteroids and icy comets, mainly because as Man moved out into the Solar System of his birth and investigated these two seemingly disparate bodies, he learned that they often held very similar characteristics. In a young solar system, gas and dust will come together to form the small meteoroids that, billions of years later, still rain down on all planets.  And these meteoroids will come together and form Asteroidal bodies.  Most of these, in turn, will continue on to create Planetoids, and eventually full fledged planets.  But there are regions where asteroids might survive in their pristine form.  The gravitational interactions between giant planets and central suns can conspire to prevent a planet from coalescing, and thus an asteroid belt will be formed, as was one between the orbits of Mars and Jupiter in the Solar System.  Further out in space, there will remain the almost untouched reserve of frozen cometary bodies in what is called the Oort Belt.  And of course, asteroidal bodies of all types will be nudged into wildly eccentric, often stable orbits that reach throughout a solar system.

Carbonic:  Almost exclusively of carbon compound construction, resulting in the formation of bodies from pockets of high carbon material around later generation stars choked with heavier elements; common near the galactic core. They may also form in systems where two white dwarfs have spiralled together, and the resulting circumstellar disk coalesces into bodies high in carbon. 

Metallic:  Bodies composed primarily of heavy metals. They are common around later generation stars, or massive stars whose youthful and highly intense stellar winds have scattered all lighter materials, leaving only those heavy metals from which solar system bodies can form. More

Carbonaceous:  Carbon bodies with high concentrations of heavy metals. Commonly found at the inward regions of solar systems, where lighter materials and volatiles have typically been reduced or eliminated by stellar activity. More

Silicaceous:  Primarily silicate bodies with little or no volatiles, and minor deposits of heavy metals. By and large these inward-system bodies have been without volatiles since the formation of their host systems. More

Hydronic:  Located close to the system's snow-line, these are silicaceous bodies with high instances of subsurface volatiles, typically in the form of water ice. Polar deposits in permanently shadowed regions may also be present.

Gelidic:  Located beyond the snow line of their system, these are bodies with high instances of ice, ranging from water to methane to carbon dioxide, and many other compounds besides, surrounding a core of silicate rock. The smaller bodies may be a nearly homogeneous mixture of ice and rock, due to the lack of a mass great enough to have caused layer differentiation early in the formative period. See also Centaurian Type

Oortean:  Largely icy bodies typically found in the system's Oort Cloud. However, various circumstances can perturb them into inward-system orbits, where they may make a single visit and be expelled from the system forever due to a close stellar pass, or where they may be modified by the gravitational influence of planets into shorter period orbits. Yes, these are the comets. More

Vulcanian:  These are a rather uncommon type, found in the dynamically stable close solar orbital zone of those systems that are not members of close binaries, or that do not have epistellar planets. While lacking any volatiles and possessing a relatively high density and heavy metal content, their composition is also often quite unique, as billions of years of such heat and solar radiation can cause unique mineral properties to emerge. More

PLANETOID CLASS – worlds with enough mass to pull themselves into spherical or near-spherical shapes

Planetoidal Class There are minor planets in every solar system, bodies that represent the embryos of growing planets in a young solar system, and the still born remains of planets in old systems.  Yet, despite their small size, these worlds are capable of possessing unique characteristics in nearly every facet that the larger, Terrestrial planets have.  Most have barren, cratered surfaces, but many possess surface deposits of ice, and some even have tenuous atmospheres. By definition, Planetoidal Class bodies range from 51 kilometers to 1,000 kilometers in diameter.  These small worlds also tend to be more spherical in shape, reflecting their larger sizes and greater gravity. In most cases, Planetoidal bodies initially begin to form in independent orbits, and seem to be well on the way to forming a true planet.  However, various circumstances can arrest this development, and either leave the Planetoid alone in a planetary orbit, or surrounded by other Planetoids and asteroids, as in a belt.  In the Sol System, for example, the Asteroid Belt contains many Planetoids, the largest of which is Ceres.  Quite possibly Ceres, or its large cousin Vesta, are the remnants of a failed planet.  Other Planetoids can form in the furthest reaches of a solar system, and make up the majority of objects to be found in the local Kuiper belt.  Some of these may find their way into the realm of the outer planets and remain as wanderers, or even be captured and become Jovian moons. The Planetoidal Class - More

Carbonean:  Carbon worlds of this mass have a chance to form around stars whose proto-stellar disks have developed carbon pockets within them, but they are far more common about late generation, high metal stars or even as the results of secondary planetary formation around high carbon stars such as white dwarfs.  However, worlds of this size and mass also experience some differentiation during their formation.  The cores of such worlds are dense masses of condensed graphite, though the planetoids at the higher mass range could form cores of partially crystallized diamond. 

Hadean:  Hadean worlds are fairly common in heavy-metal-rich systems. They are found in the inner region of the system, where lighter materials have been stripped away by energetic solar winds.  These planetoids are airless and have no inherent volatiles, although polar regions that never see sunlight might accrue water ice through cometary impacts.  The surfaces are heavily eroded through impacts, but the mass and density of these worlds typically ensures their survival even in the face of major impacts. Example Aung San Suu Kyi in the Bolobo system

Hygiean:  These bodies are typically quite dark, with albedos ranging from 0.03 to 0.1.  While there can be deposits of water ice or other volatiles beneath the surfaces of these planetoids, the surfaces are more often marked by craters and large boulders.  These worlds are less dense and more easily disrupted by major impacts.  The larger bodies, however, will have been differentiated through the formation process, and can have small cores of iron, with a dense mantle or rock and a crust of lighter silicates.  The smaller worlds, though, may be a relative even mixture of sparse metals and the far more common silicate rock. 

Vestian:  These planetoids are composed of dense metals and basaltic rocks, along with a large amount of silicates.  During the formation of the host solar system, these worlds will have formed much like the larger planets, through accretion of materials, and will have developed a high level of differentiation.  Their cores, small balls of iron, will have powered a very brief period of geological activity.  Surface signs of this include ancient volcanoes, rifts, and extensive magmatic flows, which often result in dark plains, small analogues to Selenian maria.  These planetoids, however, are quite rare as they typically evolve into larger worlds, or in the rush of formation that results in hundreds of such worlds, are cast out of the host system.
Example; Vesta

Cerean:  Planetoids that form from a low instance of heavy metals, and far enough from the local sun, often become Cerean planetoids.  Volatiles can be found in a subsurface layer, blanketed over by eons of impact ejecta, although there may be exposed regions hidden in permanently shadowed areas of the body.  Even at their increased distance from the local sun, such ice deposits would eventually be sublimated away by sunlight.  The cores of the bodies are more often dense rock than heavy metals, although there can be a small amount of iron present.  Geological activity on these worlds largely cease after the body begins to cool from the process of formation.
Example Ceres

Chronian:  Named after the plethora of such bodies orbiting the planet Saturn, these can be a highly varied lot.  Typically, these worlds are small and heavily cratered bodies untouched by time, save for the numerous impacts that they have suffered.  Their low mass and composition of primarily ice, with small rocky cores, are simply too small for sustained geological activity.  As such, there is an absence of atmosphere, or related surface features.  However, certain disruptions, such as through tidal flexing or other massive external forces may initiate geological forces that can completely resurface a planetoid, as well as form a minor atmosphere.  If such active worlds are positioned properly in a gas giant system, an impressive ring system may even be formed. Example Mimas

Kuiperian:  Found in the outermost regions of a solar system, these are worlds constructed from primarily ice, and are almost completely unchanged representatives from the birth of their host solar system.  Named because they populate Kuiper Belts, a typical star may host tens of thousands of these worlds.  Such belts can be considered fossil remnants of the planetary accretion disk; the inner regions of these belts typically form planets, but the Kuiper Belt is so far out that it would take billions of years to form a terrestrial-sized world.  However, the processes that form larger worlds are ongoing, and often Kuiperian worlds can thus be found with one or more moons, the results of near collisions, or even satellite-forming collisions, such as the one that formed Earth's Moon.  Example; Mary

TERRESTRIAL CLASS – worlds with an active internal geology that lasts one million years or more

Terrestrial Class Ranging in size from 1,000 kilometers and up, these are the primary worlds of interest to those beings who are so disposed to live within a natural world.  They are also among the most varied of worlds, ranging from dead and cratered wastes to hyper-volcanic cauldrons, from hellish worlds wrapped within thick primordial atmospheres to lush garden planets filled with teeming jungles and sweet blue oceans of water and life. By and large, Terrestrial worlds are the end point of planetary growth, typically forming too close to the local sun to accrue the massive amounts of material that exist aplenty beyond the snowline.  However, some Terrestrials, forming in those colder regions, migrate inward due to momentum loss with the protoplanetary disk, and before they can achieve Jovian masses end up in the inner regions, where their growth is halted and a massive planet is formed.  The vast majority of Terrestrial planets, however, are rather small worlds, perhaps averaging four to five thousand kilometers in diameter.  But regardless of their end form, life can often be found upon them.  While it may be restricted to the simplest mono-cellular microbial forms, such worlds nonetheless are the cradles of life, and can be found throughout the Galaxy.

Adamaean:  In star systems where the accretion disk is low in levels of oxygen, or rich in carbon, carbides and graphites condense out far more readily than do silicates, which make up the bulk of more common terrestrial worlds.  In these higher massed planets, beneath the surface where pressures are quite large, geological layers of diamonds typically form several kilometers thick.  These worlds also lack water, and instead have atmospheres largely composed of carbon monoxide, methane, and long-chain carbon compounds synthesized photochemically in their atmospheres.  Indeed, this last substance often precipitates and evaporates on a Carbon planet's surface, and seas and lakes of oil or tar-like substances often form.  Alternate biochemistries are quite possible. Example Solaris

Ferrinian:  These rocky worlds form either in very close solar orbits or about very hot and active suns.  In either case, much of the lighter planet-building material has been blown away by the intense young solar winds, leaving behind only the heavier elements.  Such worlds tend to be small, although they may attain very large sizes in high metal content systems.  The planets are typically heavily cratered, often with signs of primordial geologic activity.  The only atmosphere that they are likely to have is a trace layer of helium being constantly replenished and stripped away by the sun's stellar wind. Example Asterix

Hermian:  These worlds also have a relatively high metal content, but there remains a lighter, rocky crust as well.  These worlds may be formed in a similar manner to Ferrinian planets, but at  a further orbit from their sun, or they may be formed after suffering a cataclysmic impact during the formative period, in which most of the lighter rocky material is blasted out into space.  These planets are heavily cratered, with some signs of primordial geologic activity.  Their atmospheres are non-existent, save for a trace layer of helium being constantly replenished and stripped by the stellar wind.
Example Mercury

Selenian:  Selenians are the archetypical "dead world", planets that have almost no heavy metals, and almost no geologic activity.  Typically these worlds are formed in low metal systems.  Also, they might be formed through the collision of two bodies during the earliest formative periods of a solar system.  The two bodies typically meld together, along with most of the original heavy metals, while the remaining lighter material (if several other aspects to the collision have been satisfied) come together to form the Selenian world.  Because of this, the majority of Selenian bodies are actually moons to larger planets.  Many times there will be ample signs of past geologic activity, activity that was the by-product of the more cataclysmic form of creation.  However, a mature Selenian world will experience the occasional out-gassing of deep volatiles that work their way towards the surface on the scale of millions of years, and nothing else.  They are heavily cratered worlds, and typically devoid of any form of atmosphere. Example: Luna

EoGaian:  Terrestrial worlds of average mass and ongoing geological activity form thick primal atmospheres while between the ages of 100 and 800 million years.  During this period the earliest oceans may form, and indeed some of the earliest forms of life might evolve, albeit very primitive microbial-monocellular in nature.  The worlds themselves are wrapped within a dense atmosphere of methane, carbon dioxide, and even varying amounts of primal hydrogen and helium.  In many cases, this atmosphere is reduced through the slowdown of the geological cycle, although some worlds may lose much of their atmospheric mass because of tremendous impacts with moon-forming planetoids.  If the world is massive enough and the atmosphere is not lost, the planets may well evolve into Cytherean Types as they mature.
Example Arcadia (before Terraforming)

Arean:  Perhaps the most common of the Terrestrial Group, these are worlds whose carbon cycle has long since broken down due to the cessation of geological activity.  The planetary atmospheres and magnetic fields are typically quite sparse as a result, and the surface often retains features first laid down during the planetary formation period.  These worlds may also experience geological upswings, either due to some outside influence, or a build up of internal heat over the eons.  During these periods, the planet may be habitable, but this will likely last only for a few ten to hundreds of millions of years. Example; Mars

AreanLacustric:  These are typically young Arean worlds which retain enough geological activity so that the carbon cycle remains active, but only just.  Volcanism continues at a high enough rate to maintain a relatively thick atmosphere, composed largely of carbon dioxide and methane, while on the surface large seas and oceans may aid in a stunted form of plate tectonics.  However, as the planet ages and geological activity lessens, the atmospheres become thinner and the planet becomes colder, until finally the world evolves into the common Arean form. Example Deucalion (preterraformig)

Cytherean:  These are hellish planets, often termed “Venusian” after the prototype world in the Sol System, their trademark thick atmospheres formed by unrelenting volcanic activity and the buildup of greenhouse gases over several hundred million years.  As such, the planetary carbon cycle has broken down and completely ceased due to the resulting loss of water from the surface and the atmosphere.  Initially, these worlds likely began with large amounts of water, but its loss causes the tectonic cycle to lock up and the atmosphere is no longer processed into the planet's crust, while out-gassing volcanoes continue to add to the atmosphere.  Eventually an atmosphere hundreds of time as thick as a standard Gaian world's is formed, while the surface is riddled with volcanoes.  These volcanoes also thicken the surface crust, eventually to the point where much of the activity is literally penned beneath the surface.  Every few hundred million years, however, this activity reaches a point where the entire surface of the planet turns over in a planet-wide catastrophe, and the thickening process begins again once the internal heat has been released. Example; Venus (before terraforming)

Pelagic:  While these worlds retain a massive atmosphere rich in carbon dioxide and thus a heavy greenhouse effect, there is also such a large amount of water in the atmosphere and on the surface that a point is reached where a balance is maintained between the heat and pressure of the atmosphere, and the world-girdling ocean.  The atmosphere tends to meld almost imperceptibly with the oceanic surface, and the upper levels of that ocean can be well in excess of the boiling point of water.  However, deeper in the ocean temperatures can be of a more temperate nature, and at the oceanic floor the ambient water temperature may actually be below freezing, but kept liquid due to pressure and salinity.  Life may evolve here, even to the point of multicellular macroforms, typically clustered about geothermal hotspots, though many forms might eventually colonize the temperate mid-levels of the ocean. Example Abbas

Gaian:  These are the worlds that Humanity seeks the most, and yet they can come in a wide variety of forms, even when apparently identical to Earth.  In the most general of terms, however, Gaian planets are worlds that have a self-perpetuating tectonic cycle maintained by the planet's inner heat and the lubricating effect of the oceans.  The presence of life aids in maintaining the oceans and the atmosphere, just as the oceans and atmosphere allow for the presence of life.  Gaian worlds are among the most complex of planetary systemics.  The tectonic plates of a Gaian world form early on in the planet's history, but can significantly change over periods of hundreds of millions of years.  Some Gaian worlds have numerous and small plates, while others have only a few very large plates.  These factors often determine the size of the continents and oceans.  The atmosphere of a Gaian world is formed by volcanic out-gassing, but also maintained and often transformed by the presence of life.  While certain elements may vary, for the most part oxygen and nitrogen are the most common and most essential parts of these atmospheres.  Life itself can become quite prolific and varied, even producing sapient species.  But it is also fragile, and though microbial life is often difficult to eradicate, it does not take much of a global temperature or environmental change to wipe out much of the higher forms.

MesoGaian:  A world that supports extensive microbial biomes in its oceans and other regions, but which has not yet seen the development of more complicated forms of life.  The atmosphere often remains largely carbon dioxide and nitrogen in nature, although it may be in the process of turning over into a clearer, oxygen atmosphere as life makes the transition from anaerobic forms to aerobic forms. Example Eostremonath (preterraforming)

GaianTundral:  In its youth, certain conditions may contribute to initiate a runaway glaciation on a Gaian world.  The largest limiting factor to this is the presence of life;  however, the absence of a large amount of biomass, even in the form of microbial life, along with certain continental configurations, can foster the unrestricted growth of the polar caps and the freezing of the oceans.  At the height of this climatic episode, the oceans can freeze up to depths of several hundred meters, and even the equatorial oceans may be covered  Ironically, so much ice in the oceans precludes much atmospheric moisture, and so mountain glaciers tend to find their growth arrested, and surface winds may even erode them to a great degree.  The skies are quite clear, and the continents are almost completely dry, covered in freezing deserts reminiscent of the dry, ice-free valleys of Earth's Antarctica.  However, the slow accumulation of carbon dioxide in the atmosphere, released by volcanic activity, will eventually bring about a catastrophic greenhouse effect, melting these worlds in the space of only a few tens to hundreds of thousands of years.  The planet then falls into a period of acidic greenhouse (see below), and the entire cycle may continue over several hundred million years until continental arrangements and the development of life breaks the cycle. Example Arcadia (post terraforming)

Campian:  These worlds are Gaian in nature, with rich biomes and a planet-wide ecosphere, yet with a percentage of open water less than half the planetary surface.  As such, the climates of these planets are quite dry, with desert zones covering most of the inland regions, and over all rainfall relatively low even in the polar or tropical latitudes.  The surface oceans, better characterized as landlocked seas, have a high salinity, and generally sport biomes highly adapted to such conditions.  Indeed, a sudden influx of less saline water has been known to cause marine mass extinctions. Example Ribblehead (post terraforming)

Paludial:  These Gaian worlds possess a typical oceanic cover ranging from 50 to 85% of the surface.  However, what sets them apart from typical Gaian worlds is the low topography of the terrestrial regions.  Some such worlds may in fact have continents that are little more than chains of islands and swamp-covered expanses.  The climate tends towards tropical, and heavy vegetation can be found covering nearly all land areas.  The warm climate, fostered by nearly unrestricted flow of weather patterns, keeps even the poles from freezing in the winter.  In essence, these are the archetypical jungle worlds.  However, future tectonic movement can raise the topography and change global climate drastically. Example Trees

EuGaian:  These are the blue-green marbles, the gems of the Galaxy.  From a simple visual identification, it can be deduced that these worlds will have thriving biospheres with a long and rich evolutionary history.  Oceanic cover ranges between 50 and 85%.  Intelligence may even develop on such planets.  Of course, the trace biochemical make up of these worlds might be incompatible with Earth life, or there may be other factors that make such planets marginally or completely uninhabitable.  Regardless, taken as a singular, EuGaian worlds are Edens in the stark desolation of space. Example; Earth

Chlorine (Halogenic) World:  Large quantities of hydrochloric acid are found in a mix with the planet's water, creating an atmosphere of oxygen and chlorine.  Photosynthetic life tends to be highly dominant. Example; Chorus

To'ul'hese World:  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

BathyPelagic:  These are Gaian worlds where oceans cover the surface anywhere from 85 to 100%.  Most often, these planet wide oceans are the result of low continental topography and the lack of any surface ice, both conditions which conspire to raise ocean levels.  As such, some of the richest biomes may be flooded continental shelves.  Rarely do these worlds have no land whatsoever;  an active planetary geology almost guarantees that there will be volcanic islands or small tectonic rafts.  At the low end of the extreme, small and isolated continents will be the norm. Example Pacifica

PostGaian:  As a sun ages and evolves, so do its planets.  Gaian worlds perhaps evolve more than most, simply because their delicate biospheres transform and fade, an effect which influences the entire world.  As the sun brightens, the oceans begin to evaporate, plunging the world into a Pelagic type world, where the atmosphere has thickened greatly and merges almost imperceptibly with the 200 degree oceans.  But a critical point is eventually reached where there is catastrophic atmospheric and surface water loss.  The sheer heat of the sun drives away the protective atmosphere, the oceans dry, and what is left is a desert world with only deep basins of highly saline seas, seas that have lifetimes measured in the thousands of years.  A highly evolved PostGaian world will be completely waterless, its atmosphere a relic of its habitable past.  The geologic cycle of these worlds has largely ceased, although some remaining volcanism and minor tectonic activity might linger, slowly turning the atmosphere unbreathable as carbon dioxide begins to build.  Life remains on the planet, reduced to extremophiles, huddled beneath the surface, away from the deadly heat, perhaps sequestered in underground oases where large amount of liquid water are preserved.  Example Oshiq

LithicGelidian:  These worlds form beyond the snowline of a solar system, and are worlds of varying size formed from a combination of rocky and icy materials.  The surfaces of these worlds are typically heavily cratered, although there may be surface evidence of past geological activity.  Some of the worlds may even have atmospheres of varying degrees, due to the slow erosion of their surfaces by the weakened solar winds, or relic atmospheres formed by major geological events that occurred due to extra-planetary influences. Example; Merrion

Europan:  In essence, these are LithicGelidian worlds with a remarkable consequence of their tidal stretching.  The surfaces of these worlds are relatively smooth, the crust being made up of ice that ranges from less than a kilometer to several tens of kilometers in thickness.  The surface smoothness is a result of that crust constantly being moved and resurfaced by the underlying geology, which produces an oceanic layer of liquid water ranging from just a few to hundreds of kilometers in thickness.  The depth of the ocean is directly responsible for the thickness of the crust, and worlds that are relatively heavily cratered, even though they still show surface plate movement, typically have very thin water layers, sometimes to the point of being little more than a "slush" layer only a kilometer or less in depth.  The most extreme of these worlds are constantly experiencing breaks in the surface crust, exposing the ice to the vacuum of space.  Some of these worlds may develop atmospheres if they are massive enough, but most remain barren of any sort of atmosphere. Example; Europa

Titanian:  These are worlds of varying size and masses found beyond the snow line, but which have managed to develop thick atmospheres and a geologically dynamic surface.  The atmospheres of these worlds are typically made of nitrogen and large quantities of methane, with other hydrocarbon elements as well.  Depending on the dynamics of the world, a hydrocarbon or methane liquid cycle may also be present.  Water is also present on these worlds, but because the planets are so cold, the water ice is literally as hard as granite, and indeed plays a similar role to rock on Gaian worlds.  The surface of the planet is composed of ice "bedrock", and on those worlds with liquid methane cycles, that ice can be eroded down into smaller rocks and pebbles, even sand.  Cryovolcanism also typically occurs, with melted or semi-melted water from the warm interior welling up in much the same manner as molten magma.  Life is always possible on such planets and moons, but because of the cold temperatures involved, such life would have a very low metabolism, and likely would rarely develop beyond the simplest of forms.     Example Muuhome

Ymirian:  Found in the most distant parts of the solar system, these worlds are made almost entirely of ices.  Their surfaces are highly reflective, although some are decidedly reddish in color due to organic material interacting with solar and cosmic rays.  Heavily cratered, the geologic activity on these planets is almost entirely restricted to primordial times, but may leave surface features visible for billions of years.  What little rocky material that does form with these worlds goes to form a small and non-molten core.  Typically there is no atmosphere, as nearly all gases found at the temperatures in which these worlds inhabit freeze out onto the surface. Example Tartarus

Vesperian:  Worlds that orbit a star closer than 0.5 AU, on average, tend to become tidally locked to the star in a relatively short amount of time.  Of course, these measurements depend greatly on a particular star or planet's mass and so forth, but in general the statistics are valid.  Worlds such as this can vary greatly, with remarkably different surface conditions resulting from having a permanent day and night side.  However, Vesperian worlds themselves are especially unique, for these planets have developed biospheres that are stable for hundreds of millions, even billions of years.  A remarkable set of circumstances must be met for a world to become Vesperian, and the types of stars that they orbit are almost exclusively late K and early M-type stars.  However, these worlds are so numerous that, in an overview of the Milky Way, these worlds might actually be at least as numerous as more standard Gaian Type worlds. Example; Dante

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. Example; Io

SUPER-TERRESTRIAL CLASS – worlds that are extremely massive, but which have not formed a Neptunian or Jovian-type atmosphere, and possess an active internal and surface geology

Pyrothalassic:  In a tight solar orbit, these extremely hot worlds are composed primarily of rock, their thin crusts riddled with tectonic activity.  This activity may often be to such a degree that there are standing lakes or even oceans of magma.  The surface of these worlds can be completely turned over in a matter of years.  The atmospheres are thick and dense, and marked by a thick layer of super condensed volatiles produced by the geological activity. Example  Bremen

Panthalassic:  With masses ranging from 8.0 to 13.0 that of Earth, Panthalassic worlds are actually best described as aborted gas giants.  During the early formative period, swift-growing gas giants often migrate inward through the protoplanetary disk.  However, past a certain point, called the snowline, abundant icy materials used for gas giant growth become unavailable, and instead only rocky material of a lesser amount is used for planetary development.  These worlds thus largely stop growing when they migrate inward, but remain composed primarily of icy materials.  In the warmer region of a solar system, they then develop tremendously deep oceans and thick atmospheres. Example Panthalassa

NEPTUNIAN CLASS – 0.03 to 0.2 Jupiter masses

CryoJovian:  These worlds do not have upper level clouds because it is too cold for condensates to form, although some latitudes may have methane clouds, reflecting local warm climes.  The result is also a Jovian world that can have a variety of blue hues, although atmospheric haze could mute the color.  These worlds are also unique in that they are composed of a larger amount of rock and ice, with large cores and a less massive Jovian atmosphere than typical gas giants.  In the outer regions of a young solar system, planets form much slower, and these worlds rarely accrue enough mass to become hydrogen-helium giants. Example Poseidon

JOVIAN CLASS – 0.2 to 13.0 Jupiter masses

Jovian Class Beyond the snowline, where there is a huge amount of low density icy material available for planet building during the formation of a solar system, massive planets form.  They are the Jovians, immense worlds with no solid surface, but instead composed of hydrogen and helium, where fantastic cloudscapes extend to a limitless horizon, and where the cores are couched within such pressure that great seas of liquid metallic hydrogen roll sluggishly under nearly unimaginable constraints. By and large, Jovian planets exhibit little variation in structure, although their upper atmospheres, visible from space, can vary considerably due to many different factors.  Almost always these worlds are accompanied by large numbers of moons, primarily small rock and ice worlds, although many have at least one large satellite, nearly a planet in its own right.  Through inward migration during the formative years, many Jovians can be found in the inner solar system, some of them even within a close, torch-orbit.  Others orbit far out from the central star, many AU's away, lost in a perpetual frozen night.

HyperThermicJovian Class:  These worlds have temperatures 1,226 degrees Celsius and above, they orbit so close to their parent stars.  In these conditions clouds of silicates  can form near the top of their atmospheres, creating relatively bright atmospheres of a gray color, with an average albedo of 0.3.  The hottest worlds would vaporize  everything from sulfur, sodium,  and even lead, and would essentially have raining sand.  HyperThermicJovians of lesser mass may also lose much of their mass during their lifetimes in the face of fierce stellar winds, leaving a comet-like tail stretching for many AU in length.  However, it would be of very low visibility, and would likely require special filtering to see it clearly.  Over time, these worlds might also continue to lose orbital momentum, and could eventually spiral into their parent sun.  Extreme atmospheric loss could eventually transform such worlds into Chthonian Class planets.  Tidal locking of these worlds precludes atmospheric cloud banding. Example Osiris

EpiStellar Jovian Class:  The temperatures of these worlds range from 626 to 1,226 degrees Celsius.  At these temperatures, Alkali metals vaporize, and most commonly sodium condensates fill the atmosphere, darkening it to a grayish-brown.  The typical albedo would be 0.03.  Likely tidal locking does not allow for the formation of cloud banding.  As with HyperThermicJovian worlds, lesser-massed EpiStellar Jovians may experience atmospheric loss due to the high temperatures and strong stellar winds, in some extreme cases leading to the formation of a very faint comet-like tail, and possibly even the eventual desiccation of the world into a Chthonian planet.  This atmospheric loss would also form a tenuous envelope of bluish gas about the planet. Example Millenium

AzurianJovian Class:  The temperature range of these worlds is 76 to 626 degrees Celsius.  Water ice and other condensates cannot form at these temperatures, leaving the methane skies relatively clear, and thus quite blue due to Rayleigh scattering.  Water-ice polar caps might form, however, and it is interesting to note that "ice ages" on such worlds are possible, and are demonstrated by the expansion of water-ice clouds into the mid-latitudes.  Because of the deep blue coloration, and the lack of reflective clouds, albedos typically range around 0.12. Example Goldilocks

HydroJovian Class:  The temperature ranges of these worlds is -123 to 76 degrees Celsius, with upper atmospheres composed primarily of water ice, giving them a predominantly white appearance.  Cooler polar regions may still support the brown-stained ammonia clouds, although this coloration would typically be rather muted due to the lack of intense solar radiation.  Deeper methane clouds would be bluish.  The warmer worlds of this Class may form yellow condensates of sulfurous compounds.  The predominance of white clouds, however, would provide for high albedos of around 0.8. Example Silence

EuJovian Class:  The temperatures of these worlds range around -123 degrees Celsius, allowing for the formation of ammonia ice crystals stained by complex condensates of carbon and sulfur, which are constantly being formed by solar radiation.  Because of this, the typical color of these worlds is yellow-brown, while banding occurs in the atmosphere due to high rotational rates, although that banding's visibility may be obscured by a uniform upper atmospheric haze.  Typical albedos range around 0.57. Example Jupiter

Chthonian Class:  These worlds, at first glance, are terrestrial in nature, and indeed their atmospheres are composed only of the gases produced by the planet-wide volcanism that wracks the surface.  But these planets have a very different evolutionary history from the Terrestrial Hephaestian planets.  Rather than being hyper-volcanically active due to tidal flexing, they are so because of their closeness to their parent sun.  These worlds are the naked cores of HyperThermicJovians that have lost their atmospheres to the intense solar radiation over a period of hundreds of millions to even billions of years.  The loss increases in rate as more of the atmosphere and thus the gravitational pull of the planet decreases.  After even more time, the world may cool to form a solid surface, although being so massive (on average around 10 times the mass of Earth), internal geological processes may continue for some time. Example Sisyphos

Rogue Class (sometimes called Stevensonian Class) Planets which do not orbit any star The formation of a solar system is a chaotic process that brings about order.  Hundreds of planets may form, all orbiting together, colliding, shattering, reforming.  But as the millions of years continue, a process of attrition occurs, whereas most of these worlds are eventually lost.  Many are shattered and incorporated into the growth of other worlds.  Many more are tossed into the central sun.  And a great many indeed are tossed out into the emptiness of interstellar space. For the most part, these are cold and lifeless worlds, whatever atmospheres that they might have once had long since frozen out onto the surface and as hard as granite.  But some worlds remain heated by their internal fires, forever dark wanderers that glow in the infrared like the last ember of a camp fire.  Other worlds are gas giants, shrunken and quiescent, the tops of their clouds lost in perpetual blizzards, while in their depths the heat of their mass continues unabated, churning the atmosphere below like a boiling cauldron. It is an irony that these worlds are very common indeed, with an average solar system perhaps losing fifty or more such worlds in the first hundred million years of formation.  Indeed, they form an appreciable amount of the dark mass of the universe.  But they are difficult to find, utterly lost to the blackness and detectable only by the faint gravitational effects on light that the larger massed worlds have.

Artificial Class While not true, natural worlds, the various megastructures that have been envisioned and created by the sapients of the Terragen Sphere are worlds in their own right, many with self sustaining biospheres of various forms, and all together home to trillions of beings. While these megastructures are often quite varied in form, they can be broken down into specific Types, based on design lineages and final constructed form.

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