These are the Mercuries, Moons, and Plutos; dwarf planets, but still bigger than small-body group objects and many moons.
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Dwarf Terrestrial Group
(Corresponds to Classes: A B C D K)
Mass: 0.0001 – 0.15 Earth. Most massive enough to sustain hydrostatic equilibrium and support geological activity due to tidal forces, although the lesser ex’s are only roughly spherical and tend to be geologically quiescent.
Mass: 0.0001 – 0.15 Earth. Most massive enough to sustain hydrostatic equilibrium and support geological activity due to tidal forces, although the lesser ex’s are only roughly spherical and tend to be geologically quiescent.
Protothermic
– proto-planetary (Corresponds to Class B)
– still forming.
Surfaces: often partially to completely molten.
Atmospheres: typically thick with hydrogen and helium, as well as gases released by the
– proto-planetary (Corresponds to Class B)
– still forming.
Surfaces: often partially to completely molten.
Atmospheres: typically thick with hydrogen and helium, as well as gases released by the
massive geological activity; still suffer major impact events.
In general, their ages are < between 10 and 100 MYO. Prior to this, they are still accreting mass at very high rate, and after this point the surface, though still occasionally experiencing major impacts, have largely cooled, forming the earliest crust.
In general, their ages are < between 10 and 100 MYO. Prior to this, they are still accreting mass at very high rate, and after this point the surface, though still occasionally experiencing major impacts, have largely cooled, forming the earliest crust.
- Proto-Ferrinian (Corresponds to Classes: X/Z)
Surfaces: extremely hot or even molten.
– very high metallic content, will eventually cool down into iron-rich bodies.
Typically found in orbit of high mass or high metal stars.
– very high metallic content, will eventually cool down into iron-rich bodies.
Typically found in orbit of high mass or high metal stars.
- Proto-Lithian: (Corresponds to Classes: X/Z)
Surfaces: extremely hot or even molten.
Composed: primarily of silicates.
common in most systems.
Composed: primarily of silicates.
common in most systems.
- Proto-Carbonic: (Corresponds to Classes: X/Z)
Surfaces: extremely hot or even molten.
– carbon-rich, fairly common.
– tend to appear more in high-massed systems.
– carbon-rich, fairly common.
– tend to appear more in high-massed systems.
- Proto-Gelidian:
Surfaces: hot.
– high instances of geological activity.
– outer regions of a solar system.
– primary building material is water.
May possess significant atmospheres and regions of liquid water on their surfaces.
As the world ages and cools, the atmosphere and liquid will freeze out, while the heavier silicates and metals will have since sunk to form the body’s core.
Geo-Passive
(Corresponds to Class C)
– do not sustain continuous or intermittent geological activity.
Surfaces: largely unchanged since the early period of planetary formation.
– do not sustain continuous or intermittent geological activity.
Surfaces: largely unchanged since the early period of planetary formation.
- Ferrinian:
– dormant
Composed: primarily of metals.
Most commonly found orbiting F-type and earlier stars, or in high metallicity systems.
- Lithic:
– dormant.
Composed: largely of silicates.
– common in all star systems.
Janian
– tidally locked to their star.
Silicate rich.
Night-side: ice caps; the result of trapped volatiles either native to the world and coming from the now vanished primary atmosphere, or delivered via cometary impacts over the eons.
Hermian
hot.
silicate.
large metallic cores.
relatively thin crusts. Early catastrophic loss of mass through major impacts early in the world’s history are the typical cause for such geological configurations.
Vestian
Silicate-rich.
– ample evidence of a geologically active past, beyond the formation process.
– typically no atmosphere.
– quite common as moons, or within inner solar system regions which experienced extensive tidal disruption early in the system’s history.
Selenian (Corresponds to Class C)
low metal.
Silicate-rich.
These are typically formed through the collision of two large bodies during the early formative period of a solar system. In such collisions, the higher massed world will absorb most of the heavy metals, while the lighter materials tend to aggregate into a separate body. As such, these worlds are most often found as moons around much larger bodies. They may also form normally within low metal systems. Those forming via collisions tend to have large amounts of evidence for a brief and active geological phase, the result of the formation of the body and subsequent major impacts. Mature Selenian worlds, however, are almost completely geologically inert, with only the occasional out-gassing of volatiles that have been working their way to the surface for hundreds of millions of years. Such out-gassing is very brief and locally powerful, but makes little impact on the world in general.
Atmospheres: either entirely absent, or transient due to various circumstances, such as major cometary impacts or extremely rare major out-gassing events.
Cerean
low metal.
Silicate-rich.
– significant amount of volatiles, typically in subsurface deposits or geological layers.
- Carbonian:
dormant ,
largely composed of carbon, carbides, or hydrocarbon compounds.
- Gelidian: (Corresponds to Class D)
– dormant.
Composed: largely of ices.
Orbit: beyond the snow-line
- Stygian:
– survived the movement of their primary star off of the main sequence, and its subsequent evolution towards a stellar corpse.
Surfaces: show ample evidence of transformation due to the primary’s stellar evolution.
Geo-Thermic
(Corresponds to Class Q)
– sustain regular or intermittent geological or geothermal activity due to temperature differences caused by highly eccentric orbits.
– sustain regular or intermittent geological or geothermal activity due to temperature differences caused by highly eccentric orbits.
- Phaethonic
(Corresponds to Classes: X/Z)
Metal-rich.
– intense volcanism as they approach their parent star (orbit eccentric) at extreme epi-stellar distances.
Core: may not be geologically active,
Surface: is driving force behind the intermittent geology as the crust continually melts and re-cools.
– named after Phaethon of Greek mythology, who drove his solar chariot too close to the Earth, scorching it.
Metal-rich.
– intense volcanism as they approach their parent star (orbit eccentric) at extreme epi-stellar distances.
Core: may not be geologically active,
Surface: is driving force behind the intermittent geology as the crust continually melts and re-cools.
– named after Phaethon of Greek mythology, who drove his solar chariot too close to the Earth, scorching it.
- Apollonian X/Z
Silicate-rich.
intense volcanism as they approach their parent star (orbit eccentric) at extreme epi-stellar distances.
core may not be geologically active.
surface is the driving force behind the intermittent geology as the crust continually melts and re-cools.
- Sethian X/Z
carbon-rich.
experience intense hydrocarbon volcanism as they approach their parent star (orbit eccentric) at extreme epi-stellar distances.
core may not be geologically active.
surface is the driving force behind the intermittent geology as the crust continually melts and re-cools.
named after Seth of Egyptian mythology, who protected the sun god Ra during his nightly journey through the underworld.
- Erisian:
icy.
experience cryo-volcanism or crustal evaporation as they move in their elliptical orbit to within the snow-line.
named after Eris, the Greek goddess of chaos, as well as the largest example of such a body in the Sol /Ra system.
Geo-Tidal:
continuous geological activity due to tidal flexing. The level of activity can range from nearly constant resurfacing to regular cryo-volcanic out-gassing.
Some are even able to sustain clement environments suitable to the development of simple or complex life.
continuous geological activity due to tidal flexing. The level of activity can range from nearly constant resurfacing to regular cryo-volcanic out-gassing.
Some are even able to sustain clement environments suitable to the development of simple or complex life.
- Hephaestian:
(CLASS E in Star Trek)
the most geologically active of planets.
surfaces almost entirely molten, and change constantly. entire planetary map can be changed within <1 year Standard.
- Hebean K?
Named after Hebe, the Greek goddess of youth
silicate-rich.
highly geologically active, large regions of stability.
atmosphere thickness can vary, standing water typical only for those larger-massed bodies that have a high level of activity and a resulting thick atmosphere.
average age of surface no more than 3 MYO, much like active Terrestrial worlds.
- Promethean:
silicate-rich, through a naturally balanced amount of tidal flexing, developed a full geological cycle similar to plate tectonics. Water oceans are a part of this process,
and life, even advanced multi-cellular biomes, can be found.
Appear: From the surface, or from orbit, indistinguishable from the Gaian worlds. However, the processes which keep them habitable are far different.
Eo-Promethean:
Age: roughly 800 MYO – 3 BYO,
relatively warm and wet alkaline environment,
thick atmosphere rich in carbon dioxide and methane, along with a hydrocarbon haze..
The first oceans formed during the earliest part of this period, as will have the earliest forms of life.
Meso-Promethean:
Age: roughly 3 – 4 BYO,
a relatively warm and wet alkaline environment,
thick atmosphere has little / no methane, but which remains thick with carbon dioxide.
Single-celled simple life forms remain dominant, although towards the end of this period the first multi-cellular forms will typically begin to appear. Also towards the end of this phase, these life forms will typically begin to infuse large amounts of oxygen into the atmosphere, transforming the entire biosphere.
Eu-Promethean:
can be characterized as being “mature”, in that their biosphere is fully formed. life has come to fill nearly every ecological niche possible.
rich nitrogen-oxygen atmosphere,
remain geologically active, distinct divisions between terrestrial and oceanic crusts.
Bathy-Promethean:
formed with a large amount of water, the result being that nearly the entire surface if covered by deep oceans.
geological: cycle continues normally, however, with the occasional volcanic island or micro-continent being formed before the ocean erodes it away, within only a few tens of millions of years.
Amu-Promethean:
mature,
but they orbit at a further distance from their star than other Promethean worlds,
and have ammonia as a part of their biosphere. oceans are heavily infused with ammonia, life forms are reliant upon it as a part of their biochemical makeup.
the presence of this ammonia allows the surface water to remain unfrozen.
Thio-Promethean:
mature,
orbit furthest distance possible from their star and remain biologically viable. This is due to the presence of large amounts of methane, from the oceans to the life forms present.
because of the low temperatures, life may not develop into complex forms for billions of years, possibly taking longer than the main sequence lifespan of their star.
- Lokian:
the most active of carbon planets,
surfaces almost entirely molten, a geology which changes on an almost yearly basis.
carbon-analogues to Hephaestian worlds.
- Idunnian
Named after Idunn, the Norse goddess of youth,
carbon-rich ,
highly geologically active, possess large regions of stability as well.
atmosphere can vary in thickness, with standing liquid ammonia typical only for those larger-massed bodies which have a high level of activity and thus thicker atmospheres.
average age of the surface is no more than 3MYO.
carbon analogues to Hebean Type worlds.
- Burian
carbon-rich,
through a naturally balanced amount of tidal flexing, have developed a geological cycle similar to plate tectonics.
Ammonia oceans, life, and even advanced biomes can occur,
Appear from the surface they are almost indistinguishable from Amunian Type worlds, though the processes which keep them habitable are quite different.
often considered to be the carbon equivalent of Promethean worlds.
Temp Liquid water not possible, even when mixed with ammonia; water ice does occur, and is typically rock-hard, forming the bulk of the crust and mantle.
- Atlan
icy,
through a naturally balanced amount of tidal flexing, has developed a cryo-geological cycle similar to plate tectonics.
Methane oceans, methane-based life, and even advanced biomes can occur.
surface : almost indistinguishable (appear) from Tartarian Type planets, but the processes which keep them habitable are far different.
considered methane-equivalents to Promethean worlds.
Temp Liquid water not possible beyond thermal regions, even when mixed with methane, and instead occurs as granite-hard deposits, forming the bulk of the crust and mantle.
- Plutonian Class C
tidally stretched,
icy,
varying degrees of cryo-volcanic and other forms of geological activity
orbit outer regions of solar systems, typically as moons to Jovian worlds, although independent bodies (R, Q, X, Z) may arise.
Europan:
tidally stretched to the point of forming subsurface oceans, which can range from being a thin slushy layer <1 km thick, to great liquid water oceans 200+ km deep.
surface covered with icy crusts, often exhibiting deformations indicative of the oceans below.
Enceladusian:
icy,
surfaces smooth and relatively crater free due to out-gassing of volatiles from subsurface reservoirs. Surface ridges and grooves cover much of the slowly dynamic surface, although there are more stable, cratered regions as well. The reservoirs themselves exist as isolated pockets of semi-liquid water, maintained as such by the slow tidal flexing.
the tidal flexing which creates these worlds is of a type far less powerful than that which creates Europan worlds.
Iapetean:
icy,
rich in carbon materials, which are marked by extensive up-wellings of hydrocarbons.
surfaces typically quite splotchy as the ice contrasts with the extremely dark hydrocarbon sediments. Major rift zones and up-welling regions are also formed by this activity, built up into tremendously tall ridges and mountains by the deposition of the heavier materials.
Tritonic:
icy ,
marked by cryo-volcanic out-gassing, although most of the surface is geologically stable.
atmosphere varies in thickness, but typically is quite thin, if present.
Standing bodies of liquid methane are possible, although rare, typically being present only near cryo-thermal regions, and when the atmosphere is thick.
Geo-Cyclic
active geology that occurs on a cyclic basis, often over a span of 200+ million years. driving force behind this cycle tends to be a slow build-up of geothermal energy, resulting in a short active phase following along quiescent phase. Other mechanisms may also be responsible.
active geology that occurs on a cyclic basis, often over a span of 200+ million years. driving force behind this cycle tends to be a slow build-up of geothermal energy, resulting in a short active phase following along quiescent phase. Other mechanisms may also be responsible.
- Arean definitely Class K, silicate-rich, typically relatively quiescent planetary cores. Atmospheres range from thick and volatile-laden to almost vanishingly thin. Age In youth : may have begun a system of plate tectonics, but the lack of a permanent presence of liquid water on the surface quickly arrested that, leaving the surface barren. The slow build up of geological energy, however, will eventually lead to much more clement conditions, and may harbor the development of simple life, or even more complex forms if there is enough time. This movement from cold and dry to warm and wet conditions is called a Sisyphean Cycle, and can conceivably be maintained for billions of years.
Meso-Arean:
intermittent geological activity, periods of freezing and thawing, massive and sudden floods and the growth of glaciers and ice caps. They represent the rise to and fall from the height of geological activity in the Sisyphean Cycle.
Eu-Arean:
the quiescent, cold, and dry phase of the Sisyphean Cycle.
surfaces barren and accumulated large number of impact craters,
atmospheres largely eroded away to only a thin covering of carbon dioxide.
may be some residual geological activity,
and even pockets of extremophile life, typically deep beneath the surface, but for the most part these worlds can be considered to be “dead”.
Arean-Lacustric:
the height of their Sisyphean Cycle, wet and clement surfaces.
Simple life is abundant, and on those more massive worlds where this phase lasts longer, more complex forms might develop.
atmosphere thick with carbon dioxide, powered by the extensive geological activity.
Temp At its height, may be too warm for polar caps.
intermittent geological activity, periods of freezing and thawing, massive and sudden floods and the growth of glaciers and ice caps. They represent the rise to and fall from the height of geological activity in the Sisyphean Cycle.
Eu-Arean:
the quiescent, cold, and dry phase of the Sisyphean Cycle.
surfaces barren and accumulated large number of impact craters,
atmospheres largely eroded away to only a thin covering of carbon dioxide.
may be some residual geological activity,
and even pockets of extremophile life, typically deep beneath the surface, but for the most part these worlds can be considered to be “dead”.
Arean-Lacustric:
the height of their Sisyphean Cycle, wet and clement surfaces.
Simple life is abundant, and on those more massive worlds where this phase lasts longer, more complex forms might develop.
atmosphere thick with carbon dioxide, powered by the extensive geological activity.
Temp At its height, may be too warm for polar caps.
- Utgardian: carbon-rich, relatively quiescent cores, surfaces: ammonia-rich. Atmospheres range from thick to only moderately so, never becoming exceedingly thin due to the distances (orbit) of such worlds from their primary star, and the ease which cold temperatures retain atmospheric gases. Slow build-up of geological activity brings these worlds from relatively dry conditions to a state where the surface is marked with liquid ammonia seas, rivers, and possibly even ammonia-based life.This Ragnarokian Cycle alternates over tens of millions of years, sometimes hundreds of millions, and it could last for billions of years.
Meso-Utgardian:
intermittent geological activity,
surfaces either slowly drying out, or marked by the thawing of ammonia reserves. They mark the rise and fall from the height of this activity cycle, and thus can have dynamic surfaces.
Eu-Utgardian:
quiescent and dry phase of the Ragnarokian Cycle.
surfaces barren, and the lack of activity lends towards the accumulation of impact craters. becomes dominated by Aeolian forces
atmospheres thinned somewhat due to the lack of surface activity,
but because of the cold temperatures typical for their orbital position, they still remain thicker than normal,
and are rich in methane.
Any advanced life that had previously managed to evolve will go extinct, although the more primitive and hardy microscopic forms will remain, typically deep beneath the surface.
Utgardi-Lacustric:
the height of their activity cycle,
resplendent with seas and even oceans of liquid ammonia.
atmospheres quite thick,
environment is warm, relatively speaking.
Life, largely dormant before hand, will expand across the surface, and given enough time may even diversify into more advanced multi-cellular forms. This phase of the cycle may last tens of millions of years, or more, largely depending on world mass and the amounts of heavy metals present.
intermittent geological activity,
surfaces either slowly drying out, or marked by the thawing of ammonia reserves. They mark the rise and fall from the height of this activity cycle, and thus can have dynamic surfaces.
Eu-Utgardian:
quiescent and dry phase of the Ragnarokian Cycle.
surfaces barren, and the lack of activity lends towards the accumulation of impact craters. becomes dominated by Aeolian forces
atmospheres thinned somewhat due to the lack of surface activity,
but because of the cold temperatures typical for their orbital position, they still remain thicker than normal,
and are rich in methane.
Any advanced life that had previously managed to evolve will go extinct, although the more primitive and hardy microscopic forms will remain, typically deep beneath the surface.
Utgardi-Lacustric:
the height of their activity cycle,
resplendent with seas and even oceans of liquid ammonia.
atmospheres quite thick,
environment is warm, relatively speaking.
Life, largely dormant before hand, will expand across the surface, and given enough time may even diversify into more advanced multi-cellular forms. This phase of the cycle may last tens of millions of years, or more, largely depending on world mass and the amounts of heavy metals present.
- Titanian: carbon-rich, relatively quiescent cores, surfaces methane-rich. Atmospheres, because it is so cold and the gases so easily retained in their distant orbital positions, are almost always thick with methane and hydrocarbons. greenhouse effect caused by methane is present, but largely negligible due to the distance from the parent star. Over time, and because of the lack of heavy geological activity, the atmosphere may slowly diminish, turning the world into a frozen body over the course of 7+ billion years. Only renewed activity will reform the greenhouse environment, and the seas will again thaw. This Titano-malchian Cycle alternates over 20+ million years, sometimes 200+million, and could last for 2+ billion years.
Meso-Titanian: intermittent geological and cryo-volcanic activity,
surfaces either drying out and freezing, or marked by the thawing of methane reserves. These worlds mark the rise and fall from the height of this cycle, surfaces have potential for being quite dynamic.
Eu-Titanian: quiescent and dry phase of the Titano-malchian Cycle.
surfaces are barren, and the lack of activity lends itself towards the accumulation of impact craters. become dominated by Aeolian forces
atmospheres will become less dynamic during this phase, but will experience relatively little loss of mass overall.
Any advanced life that had managed to evolve during the active phase will likely go extinct, leaving only the hardier extremophile forms.
Titani-Lacustric: the height of their activity cycle,
resplendent with seas and even oceans of liquid methane.
atmospheres quite thick with extensive hydrocarbon hazes,
environment is warm, relatively speaking.
Life has potential for developing into complex forms, but because of the cold environment, this is not very common. This phase of the cycle may last 20+ million years, or more, largely depending on world mass and the amounts of heavy metals present.
surfaces either drying out and freezing, or marked by the thawing of methane reserves. These worlds mark the rise and fall from the height of this cycle, surfaces have potential for being quite dynamic.
Eu-Titanian: quiescent and dry phase of the Titano-malchian Cycle.
surfaces are barren, and the lack of activity lends itself towards the accumulation of impact craters. become dominated by Aeolian forces
atmospheres will become less dynamic during this phase, but will experience relatively little loss of mass overall.
Any advanced life that had managed to evolve during the active phase will likely go extinct, leaving only the hardier extremophile forms.
Titani-Lacustric: the height of their activity cycle,
resplendent with seas and even oceans of liquid methane.
atmospheres quite thick with extensive hydrocarbon hazes,
environment is warm, relatively speaking.
Life has potential for developing into complex forms, but because of the cold environment, this is not very common. This phase of the cycle may last 20+ million years, or more, largely depending on world mass and the amounts of heavy metals present.
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Class A:
Terms: dwarf, geo-thermal
Age: 0-2 BYO, very young
Orbit: variable solar
Diameter: 1,000-10,000 km, small
Mass: ~.005-.4 Earth masses
Solar System Zone: Hot / Ecosphere / Cold
Surface: usually partially molten, barren
Composition: N/A
Temperature: very hot, regardless of star proximity
Day / Night: N/A
Light-side / Dark-side: N/A
Gravity: ~.01-.5 G
Tectonics: usually high volcanic, traps CO2 in atmosphere
Atmosphere: none / very thin
Composition: carbon dioxide, hydrogen
Density: quite dense
Pressure: (atm) 0-.1 atm
Core: N/A
Hollow: Yes
Composition: N/A
Abundant / rich in: carbide
Evolution: if volcanic activity ceases, cools to become Class C
Life: none
Appearance:
From Space: dark lava subtly and/or brightly glowing
Examples: Gothos
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Class B:
Terms: dwarf, geo-morteus
Age: 0-10 BYO, young
Orbit: tight solar
Diameter: 1,000-10,000 km, small
Mass: ~.005-.4 Earth masses
Solar System Zone: Hot
Surface: partially molten, highly unstable
Composition: N/A
Temperature: extreme
Day / Night: 450 / -200
Light-side / Dark-side: N/A
Gravity: ~.1-.5 G
Tectonics: active volcanoes
Atmosphere: usually very thin
Composition: helium, sodium
Density: N/A
Pressure: (atm) ~.1-.25 atm
Core: N/A
Hollow: Yes
Composition: N/A
Abundant / rich in: N/A
Evolution: N/A
Life: N/A
Appearance:
From Space: rusty mud and lava subtly and/or brightly glowing
Examples: Mercury (although it lacks volcanoes and is solid), Char, Nebhilum
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Class C:
Terms: dwarf, geo-inactive
Age: 2-10 BYO, intermediate
Orbit: tight solar
Diameter: 1,000-10,000 km, small
Mass: ~.005-.4 Earth masses
Solar System Zone: Ecosphere
Surface: barren
Composition: may be covered in ice and/or frozen gases
Temperature: cold
Day / Night: N/A
Light-side / Dark-side: N/A
Gravity: ~.2-.5 G
Tectonics: geologically inactive
Atmosphere: none
Composition: N/A
Density: N/A
Pressure: (atm) 0 atm
Core: geologically inactive
Hollow: Yes
Composition: N/A
Abundant / rich in: N/A
Evolution: N/A
Life: _
Appearance:
From Space: sooty, lunaresque
Examples: Pluto, Psi 2000
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Class D:
Terms: asteroid, moon, planetoid / dwarf, Plutonian object
Age: 2-10 BYO, intermediate
Orbit: variable solar
Diameter: 100-4,000 km, tiny
Mass: ~.001-.1 Earth masses
Solar System Zone: Hot / Ecosphere / Cold
Surface: barren, cratered
Composition: N/A
Temperature: N/A
Day / Night: N/A
Light-side / Dark-side: N/A
Gravity: ~.05 G
Tectonics: geologically inactive
Atmosphere: none / very thin / tenuous
Composition: N/A
Density: N/A
Pressure: (atm) 0-.1 atm
Core: primarily ice; not a true ‘planet’
Hollow: Yes
Composition: _
Abundant / rich in: N/A
Evolution: N/A
Life: none
Appearance:
From Space: limestone covered, lunaresque
Examples: Ceres, Eredas-Il, Moon / Luna, Pluto / Plutonians
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Class K:
Terms:
Age:
Orbit:
Diameter:
Mass:
Solar System Zone:
Surface:
Composition:
Temperature:
Day / Night:
Light-side / Dark-side:
Gravity:
Tectonics:
Atmosphere:
Composition:
Density:
Pressure: (atm)
Core:
Hollow:
Composition:
Abundant / rich in:
Evolution:
Life:
Appearance:
From Space:
Examples:
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