Hövnísan Planeto-Taxonomy Standards Technology / Science in The Rosepetal | World Anvil

Hövnísan Planeto-Taxonomy Standards

Public planetology taximetrics record
Property of the Royal Atheneum of Hövnís, Eörpe

Here at the Royal Atheneum of Hövnís, Eörpe, planets and other stellar objects are categorized primarily through phenetic taxonomy, meaning that they are grouped by overall similarity – usually in morphology and other observable traits. The most common differentiations made are base composition, size and mass, median temperature, baryonic pressure, gravitational force, and atmosphere contents.  

Definition of Planet & World

Within the context of this documentation, a planet is defined as 'an object in space that enough mass and gravitation to be near-spheroid due to hydrostatic equilibrium but has never undergone nuclear fusion'.
Most planetary bodies are described to have between two and four layers: atmosphere, crust, mantle and core.
— Notation by Dr. Tybulus Svilen
  The term world is in all contexts considered synonymous to habitable planet, with the definition 'a planet with a biosphere capable of sustaining complex lifeforms'.  

The Taxonomic Hierarchy

The taxonomic hierarchy originally featured four base levels, with up to two sublevels each (prefixed Sub- and Infra-). Recently however, it was decided to include an additional fifth level to aid in grouping planets based on their atmospheres and habitability.  
All levels feature a limited set of categories with fixed names for classifying planetary bodies. Any additions to these need to have substantial scientific basis, and the process to have them formally accepted for use is usually long and thorough.
The planeto-taxonomic hierarchy still lacks Latirönen naming. Planetologists are clearly not quite as enthusiastic for fancy terminology as zoologists are.
— Notation by Dr. Eirin Karst
 

Domain

The first level, the domain, groups a planetary body based on which galaxy it's found within. Listing all currently known galaxies is beyond the scope of this document but our own galaxy and its satellites are considered the most important and most well-explored to date.    

Subdomain

The subdomains groups planetary bodies based on what they are orbiting, if anything.  

Solaroid

A solaroid planet is a main body within a solar system, orbiting the system's central star at a stable distance.

Lunaroid

A lunaroid planet is a planetary body that orbits another planetary body, such as a moon.

Rogue

A rogue planet is a planetary body that doesn't orbit something else, and is either still or moving on its own through the vacuum of space.
 

Sphere

The sphere taxonomic level groups planetoids based on their mass and size.   All planetoids used to be grouped based on a singular scale of measure, but in later revision this was shifted to encompass four different scales depending on what class/subclass a planetoid was categorized in.
All stellar objects are measured in the Stellar Mass (Sm) standard unit.   1 Sm is equal to the mass of the planet Eörpe, which is 5.973e10 Kg.
— Notation by Dr. Tybulus Svilen
 

Rocky/Cryonic

Rocky and cryonic planets are typically the smallest planetary bodies, and are rarely larger than 10 stellar masses.   They are grouped as follows:  
  • Diminutive (< 0.005 Sm)
  • Tiny (0.005 to 0.05 Sm)
  • Small (0.05 to 0.5 Sm)
  • Medium (0.5 to 2 Sm)
  • Large (2 to 10 Sm)
  • Massive (> 10 Sm)

Oceanic

Oceanic planets tend to be larger than rocky and cryonic ones, but don't become as large as the gaseous.   They are grouped as follows:  
  • Tiny (< 0.3 Sm)
  • Small (0.03 to 5 Sm)
  • Medium (5 to 10 Sm)
  • Large (10 to 30 Sm)
  • Massive (> 30 Sm)

Glaciliquid Gaseous

The glaciliquids were given their own scaling for mass due to never reaching the gargantuan sizes of other gaseous planets.   They are grouped as follows:  
  • Tiny (< 5 Sm)
  • Small (5 to 10 Sm)
  • Medium (10 to 20 Sm)
  • Large (20 to 50 Sm)
  • Massive (> 50 Sm)

Other Gaseous

Gaseous planets are among the most massive stellar objects found in the Rosepetal.   They are grouped as follows:  
  • Tiny (< 150 Sm)
  • Small (150 to 300 Sm)
  • Medium (300 to 500 Sm)
  • Large (500 to 1500 Sm)
  • Massive (> 1500 Sm)
 

Division

The division taxonomic level groups planetoids based on their median temperature.   The median temperature is measured at the altitude where the atmospheric pressure is 1 Atm, or at surface level on planetoids with too low or no atmospheric pressure.  

Temperature Divisions

  • Frigid (< -180 C)
  • Cold (-180 to -100 C)
  • Cool (-100 to -30 C)
  • Temperate (-30 to 55 C)
  • Warm (55 to 225 C)
  • Hot (225 to 730 C)
  • Torrid (> 730 C)
Temperatures are measured using the standard centigrade (C) scale.   The temperate span was set based on the lowest and highest temperatures between which the development of complex endemic life is considered possible.
— Notation by Dr. Tybulus Svilen
 

Grade

The grade taxonomic level groups planetoids based on their gravitational force at surface level. For gaseous planets, this is usually defined as the surface of their solid or liquid core. For oceanic planets this is usually defined as either the surface of their mantle, or as the surface of their solid or liquid core if they lack a mantle.  

Gravity Grades

  • Nullgravital (< 0.001 Gf)
  • Infragravital (0.001 to 0.1 Gf)
  • Hypogravital (0.1 to 0.5 Gf)
  • Mesogravital (0.5 to 1.5 Gf)
  • Hypergravital (1.5 to 2.5 Gf)
  • Ultragravital (> 2.5 Gf)
The standard unit of measurement is graviforce (Gf).   1 Gf is equal to the gravitational force on the surface of Eörpe.
— Notation by Dr. Tybulus Svilen
 

Subgrade

The subgrade groups planetoids based on their atmospheric pressure at surface level. For gaseous planets, this is usually defined as the surface of their solid or liquid core.  

Atmosphere Grades

 
  • Nullspheric (< 9.85e-7 Atm)
  • Infraspheric (9.85e-7 to 9.85e-4 Atm)
  • Hypospheric (9.85e-4 to 9.85e-2 Atm)
  • Mesospheric (9.85e-2 to 9.85e1 Atm)
  • Hyperspheric (9.85e1 to 9.85e3 Atm)
  • Ultraspheric (> 9.85e3 Atm)
The standard unit of measurement is also named atmospheric pressure (1 Atm).   1 Atm is equal to the atmospheric pressure at sea level on Eörpe.
— Notation by Dr. Tybulus Svilen

Recent Additions

In addition to the standard four levels of the standard taxonomic hierarchy, a new level was recently added that only applies to planets that feature an atmosphere. This also included a subtyping denoting the planet's habitability.  

Type

The typing groups planets by a set of common traits relating to their atmospheres' pressure and contents.  

Type I

This is an atmosphere that is breathable to respiration-based complex lifeforms. This typically means the atmosphere is either an oxygen, solagen, or methagen mix.   Planets with Type I atmospheres are the most common to host complex endemic life, but lifeforms are typically limited to safely breathing the gas mix present on their native planet. They will need a rebeather or filter mask in order to safely visit planets featuring a different gas mix.
 
There are still ongoing debates about splitting Type I atmospheres into separate types depending on if they're oxygen-, solagen-, or methagen-base.
— Notation by Dr. Tybulus Svilen
 

Type II

This is an atmosphere that typically contains sufficient levels of gas mixes to be breathable for lifeforms adapted to Type I atmosphere, but even short term exposure can be detrimental to their health.   Common causes are either the atmospheric pressure being too low or high, or due to the presence of contaminants or other trace gases. Planets with a Type II atmosphere can host complex endemic life, but that's much rarer than for Type I planets.

Type III

This is an atmosphere that requires most lifeforms adapted to Type I & II atmospheres to wear a rebreather or filter mask in order to not suffer immediate or eventual impediments or incapacitation.   Common causes are lacking appropriate levels of needed gases, containing contaminants and/or trace gases, or having a too low or high atmospheric pressure. It's rare for planets with Type III atmospheres to host complex endemic life.

Type IV

This is an atmosphere that requires lifeforms adapted to Type I & II atmospheres to use an enviromental suit, and in some cases even that may not fully ensure their safety.   Common causes is the atmosphere being highly toxic or flammable, or it having an extremely low or high atmospheric pressure. A rare few planets with a Type IV atmosphere have been found to host endemic life in the form of unicellular extremophiles.
 

Subtype

Planets with Type I & II (and sometimes III) atmospheres are commonly divided into a subtype depending based on a more generalized degree of habitability for complex lifeforms.  

Habitable

This subtyping covers planets that either naturally or through bioengineering features a biosphere with a Type I atmosphere.   Some bioengineered planets may require artificial enviro-control to remain stable and safe for habitation.

Semi-Habitable

This subtyping covers planets that most commonly are of a Type II or III atmosphere and hosts endemic life.   Species adapted to Type I atmospheres can usually survive and live on the planet but likely need to live part- or full-time within an enclosed environment such as a domed city or other enviro-controlled habitat.

Bioformed

This subtyping covers planets that through advanced bioengineering have acquired a habitable or semi-habitable biosphere. It also includes previously habitable or semi-habitable planets that have been significantly altered through bioengineering.
 
Most natural worlds will feature several climate zones and biomes, while bioengineered worlds tend to be far more uniform from pole to pole and have predictable weather patterns.   This is due to bioengineered worlds often requiring enviro-control technology to retain atmo- and hydrospheric stability.
— Notation by Dr. Tybulus Svilen
 

Ecumenopolis

This subtyping covers planets whose entire surface has been covered with a cityscape, fully replacing any previous natural biosphere that may have existed.   They require artifical enviro-control in order to stay habitable and comfortable for their inhabitants. Many ecumenpolises are comprised of several toplogical layers.

Skethal

This subtyping covers planets that are technically habitable to most species adapted to Type I or II oxygen-based atmospheres, but due to the biosphere being dominated by marrowblight-based lifeforms is considered extremely hostile.   Any carbon-based lifeforms present on a planet partially or fully taken over by the skethal infestation run a very high risk of being attacked and assimilated.

Class

The class groups planetoids primarily through their material composition, and secondary through the primary state of matter those compositions are in.  

Rocky

Planetoids that are composed of >50% silicate/carbide or metallic material are called rocky planets.   They are often stratified into three or more layers; featuring a solid crust, a molten mantle and a solid inner core. It's extremely rare but not unheard of for them to host an ocean instead of molten rock at the mantle.

Cryonic

Planetoids that are composed of >50% solid volatiles are called cryonic planets.   They typically have a glacial shell instead of a rocky crust, which can span all the way to its smaller and lighter core. The core is typically composed of porous rock, but some cryonic planets have them made from jumbled rock in ice.

Gaseous

Planetoids composed of >70% volatiles with no solid crust or mantle are called gaseous planets.   All gaseous planets typically consist of a solid or liquid core, surrounded by a hot mantle of supercritical volatiles, which in turn is enveloped by a gaseous atmosphere. The atmosphere is either hydrogen-helium dominant or also contains supercritical volatiles.

Oceanic

Planetoids that are composed of >70% liquid solvent with no solid crust are oceanic planets.   Some may also have their solvent stretch past the mantle and only have a semi-solid to solid core. While some may feature frozen poles and floating glacial masses, it's very rare that they feature any natural rocky/metallic-content masses either on the surface or below the surface.
 

Subclass

The subclass further splits each planetoid class into even more specific phenotypes depending specific typical combinations of material composition, level of solvent, atmospheric pressure, median temperature, and a number of geological and geographical characteristics.  
Rocky Subclasses

Aquatic


Aquatics have more than two thirds of its surface covered with solvent and lack major landmasses.   The surface landmasses that exist consist primarily of groups of islands and isles.

Arid


Arids, as their name suggest, have an overall arid climate and less than a third of its surface is covered with solvent. Precipitation is normally scarce.   They don't necessarily have a less total volume of solvent than other rocky planets but it may be located subsurface or permanently locked inside polar ice caps.

Barren


Barrens have a temperate median temperature combined with an extremely low to nonexistent atmospheric pressure. It's extremely rare that they have any solvents.   Most barrens are incapable of hosting endemic life but can be rich in mineable resources.

Calescent


Calescents feature an extremely high atmospheric pressure and are typically very hot due to the intense greenhouse effects. Some may even feature seas of molten rock.   Calescents rarely host endemic life, but those that do have only had it in the form of unicellular extremophiles in their atmospheres.

Frozen


Frozens have extremely low temperatures in combination with a low to nonexistent atmospheric pressure. Some have been found to feature frozen-form solvents.   Similar to barrens most are incapable of endemic life, but can be rich in mineable resources.

Glacial


Glacials are of cold but not freezing temperatures, with most of its surface covered with snow and ice. Larger bodies of solvent on the surface typically won't freeze through entirely.   Glacials include rocky planets undergoing an ice age but otherwise would be classified as another subtype.

Molten


Moltens reach very hot temperatures and low to nonexistent atmospheric pressure. The crust tends to be dominated by seas of molten rock. They're considered incapable of hosting endemic life.   While moltens can be rich in resources they are often considered too difficult to mine.

Semi-Volcanic


Semi-volcanics typically share all the same characteristics of a volcanic rocky planet, except that they see less overall tectonic movement. This typically means lower seismologic and volcanic activity that result in a flatter and more even terrain both above and below the sea's surface.   Most semi-volcanic planets lack certain features such as mountain ranges, ravines and valleys, and the seas and ocean rarely have deep trenches.

Tryptonic


A tryptonic planet features all of the characteristics of another subclass of rocky planet, in addition to having extensive networks of underground tunnels and caves below sea level. In addition, the subsurface needs to be the primary source of endemic life in order to be classified as tryptonic.   The most common reason for endemic life primarily developing subsurface tends to be due to the surface for some reason is close to or fully uninhabitable.

Volcanic


Volcanics are the most common subclass of habitable and semi-habitable rocky planets. They feature at least one major landmass and have more than a third of their surface covered with a solvent.   Tectonic movement and other forces create landscapes both above and below sea level with a high variety in topological differences. But it also make them very unlikely likely to become tryptonic..
 
Cryonic Subclasses

Aquatic


Aquatics have more than two thirds of its surface covered with solvent and lack major landmasses.   The surface landmasses that exist consist primarily of groups of islands and isles.

Arid


Arids, as their name suggest, have an overall arid climate and less than a third of its surface is covered with solvent. Precipitation is normally scarce.   They don't necessarily have a less total volume of solvent than other cryonic planets but it may be located subsurface or permanently locked inside polar ice caps.

Barren


Barrens have a temperate median temperature combined with an extremely low to nonexistent atmospheric pressure. It's extremely rare that they have any solvents.   Most barrens are incapable of hosting endemic life but can be rich in mineable resources.

Calescent


Calescents feature an extremely high atmospheric pressure and are typically very hot but still manage to stay solid due to the extreme atmospheric pressures. These pressures still aren't high enough however for the volatile chemicals to reach a supercritical fluid state.   Calescents rarely host endemic life, but those that do have only had it in the form of unicellular extremophiles in their atmospheres.

Frozen


Frozens have extremely low temperatures in combination with a low to nonexistent atmospheric pressure.   Similar to barrens most are incapable of endemic life, but can be rich in mineable resources and useful for collecting chemicals.

Suboceanic


Suboceanics are a very rare type of cryonic planet where the mantle consists of a solvent ocean rather than ice.   The suboceanic ocean is sometime capable of endemic life, but can very rarely support complex lifeforms.

Tryptonic


A tryptonic planet features all of the characteristics of another subclass of cryonic planet, in addition to having extensive networks of underground tunnels and caves below sea level. In addition, the subsurface needs to be the primary source of endemic life in order to be classified as tryptonic.   The most common reason for endemic life primarily developing subsurface tends to be due to the surface for some reason is close to or fully uninhabitable.

Volcanic


Volcanics are the most common subclass of habitable and semi-habitable cryonic planets. They feature at least one major landmass and have more than a third of their surface covered with a solvent.   Tectonic movement and other forces create landscapes both above and below sea level with a high variety in topological differences. But it also make them very unlikely likely to become tryptonic.
 
Gaseous Subclasses

Barren


Barrens are very rare types of gaseous planets that for one reason or another had their atmosphere and supercritical mantle stripped.   This leaves behind only a dense, rocky/metallic core.

Glaciliquid


Glaciliquids are gaseous planets composed of 80% or more elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur.   These volatile elements exist primarily in a supercritical fluid state in both the atmosphere and mantle layer due to immense temperatures and atmospheric pressures.

Gasoliquid


Gasoliquids are by far the most common type of gaseous planets. The atmosphere is often thick and composed of gases, of which 80-90% is usually hydrogen and helium.   At the mantle layer the temperature and pressure is typically high enough that the present volatile elements enter a supercritical fluid state.

Semi-Volcanic


Semi-volanics are extremely rare types of gaseous planets that may be young gaso- or glaciliquids.   These feature a semi-solid to solid mantle rather than supercritical volatiles, often in the form of a glacial shell with a lot of tectonic movement.
 
Oceanic Subclasses

Abyssal


Abyssals lacks a solid mantle layer, and instead has this region filled with additional solvent though the pressure is typically too high for complex endemic life to survive at these depths.   At the center the planet still has a solid rocky/metallic core.

Barren


Barrens are extremly rare types of oceanic planets where, for one reason or another, the atmosphere was stripped and the surface solvents evaporated as a result.   This leaves behind only a barren mantle and core.

Glacial


Glacials feature cool to cold temperatures, causing a partial or full freezing of the surface layer of its solvent.   Partial freezing is the most common, with large polar ice caps and free-floating glaciers and icebergs.

Islandic


Islandics are extremely rare types of oceanic planets that feature solid masses consisting of rock, metal, and/or ice no larger than an island.   These islands and isles are free-floating above or below the surface.

Volcanic


Volcanics are the most common type of oceanic planets that feature no crust layer but still has a mantle in addition to its core.   The mantle is often partially or fully filled with molten rock.


Cover image: by KELLEPICS

Comments

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Sep 9, 2023 19:20 by Joella Kay

This is great!

Sep 11, 2023 16:12 by Nimin N

Thank you! Glad you liked it. :)

Sep 19, 2023 12:36 by Dr Emily Vair-Turnbull

This is so fascinating and well thought out. I love the little notations by Dr. Tybulus Svilen.

Emy x   Etrea | Vazdimet
Sep 24, 2023 13:24 by Nimin N

Thank you! Happy to hear you like the notations, I thought they'd be a nice alternative to using tooltips that at the same time helps break up the texts a little. :)