Planetary Classification
(Redirected from Class Q)
Facts
- Planetary classification system established by mid-23rd century
- Descends from similar classification systems established by Vulcan Science Directorate, UESPA (ENT, TOS)
Classifications
Class A
- Geothermal rocky body
- Young world not yet solidified
- Insufficiently large to maintain atmosphere, heat following solidification
- Primarily hydrogen-based atmosphere
- Eventually cools to class C
Class B
- Geomorteus rocky body
- Orbits close to primary
- Surface temperature high; portions of surface potentially molten
- Little to no atmosphere due to heat and solar ablation
Class C
- Geoinactive rocky body
- Transition from Class A
- Geological processes largely halted
- Atmosphere cooled, potentially frozen
Class D
- Airless body, often an asteroid or moon
Class E
- Geoplastic rocky body
- Young world not yet solidified
- Essentially a large class A
- Transitions to class F
Class F
- Geometallic rocky body
- Transition from class E
- Surface partially solidified, geological and geothermal activity still high
- Largely uninhabitable by humanoid life
- Transitions to class G
Class G
- Geocrystalline rocky body
- Transition from class F
- Surface essentially solidified
- Temperatures cooling, potentially survivable range
- Thick atmosphere
- Often low oxygen content due to oxygen binding in crust
- Potentially habitable with technological aid
- Transition to class H, K-P
Class H
- Rocky body
- Very arid world
- High surface temperature
- Little to no surface water
- Atmosphere often saturated with heavy gasses or metallic vapors
- Generally uninhabitable to humanoid life
Class I
- Ice giant
- Atmospheric envelope dominated by ammonia, water, methane
- Hydrogen levels very low (20% or lower) as compared to class J planets
Class J
- Cold gas giant
- Divided into three subtypes by temperature, predominant cloud formation
- Type 1: 150K or lower, dominated by ammonia clouds
- Type 2: 150K-250K, dominated by water vapor clouds
- Type 3: 250K-800K, cloudless
- Divided into three subtypes by temperature, predominant cloud formation
- Known as Fesoan-class by Andorians (ENT Novel: Live by the Code)
Class K
- Adaptable
- Generally thin atmopshere
- Little to no surface water
- Surface conditions suitable for life with aid of pressure domes or life support technology (TOS: "I, Mudd")
- Often pre-terraforming state
Class L
- Marginal
- Transitioned from class G
- Barely habitable or habitable with minimal technological aid
- Often pre-terraforming state
- Native life often limited to flora
- Possibly in process of transitioning to class M
Class M
- Terrestrial
- Previously known as Minshara-class by Vulcan Science Directorate, Earth-type by UESPA (ENT, TOS)
- Significant surface water, below 80% coverage
- Atmosphere consisting of nitrogen, oxygen, trace elements
- Habitable by humanoid life
- Subdivided into type 1-4, indicating most to least suitable for humanoid life (TNG: "The Bonding")
Class N
- Reducing
- Thick atmosphere, often saturated with sulfur compounds
- High surface temperature due to atmospheric greenhouse effect
- Generally uninhabitable for humanoid life
Class O
- Pelagic
- Largely identical in composition and habitability to class M
- Liquid water covers 80+% of surface
- Life generally only present if sufficient landmasses to allow for mineral circulation
- Common alternative to class M planets in systems with gravitational disruption of protoplanetary disk leading to increased cometary bombardment (TNG Novel: The Buried Age)
- Examples include distant stellar companions, multiple inward-migrating Jovians (TNG Novel: The Buried Age)
Class P
- Glaciated
- Largely identical in composition to class M
- Surface temperatures below freezing
- Generally covered in water ice
- Often transitioning from prior class due to changes in available surface heat
- Scientific study often based from subglacial bases constructed on rocky core beneath planetary ocean/slush mantle, ice crust (TNG Novel: The Buried Age)
Class Q
- Variable
- Previously known as Quaris-class by Vulcan Science Directorate
- Unpredictable surface and environmental conditions
- Generally wide variations from region to region
- Often caused by variable star output, highly eccentric orbit
Class R
- Rogue
- Generally uninhabitable
- Geothermal heat can sometimes maintain ecosystem on surface
Class S
- Gas dwarf
- Generally protoplanetary stage progressing towards class I
Class T
- Hot gas giant
- Divided into two subtypes by temperature, predominant cloud formation
- Type 4: 900K-1400K, dominated by alkali clouds
- Type 5: 1400+K, dominated by silicate clouds
- Divided into two subtypes by temperature, predominant cloud formation
Class X
- Miscellaneous classification
- Any planetary status not falling under standard natural planetary development
- Unsubstantiated
Class Y
- Terrestrial
- Colloquially known as "demon"-class (VOY: "Demon")
- Extremely high surface temperatures
- Corrosive and/or toxic atmosphere
- Thermionic discharges from surface-level metallic hydrogen deposits common (VOY: "Demon")
- Planetary conditions can lead to vessel hazards even at standard orbital altitude (VOY: "Demon")
Notes
- Star Charts classifications flawed w.r.t. giant planets
- Radii are physically impossible
- Jupiter diameter ~140,000km, maximum theoretical possible planetary diameter ~400,000km, but class T planets go up to 120m km?
- Adding more mass generally tends to increase density, not radius; proximity to sun increases size but only so far
- No acknowledgement of ice giants (not widespread distinction yet at time of writing) despite physically distinct characteristics
- All Star charts giant classes are predominantly hydrogen-based, ice giants (i.e. Neptune, Uranus) are water/ammonia-based with very slim hydrogen envelopes
- All gas giants listed as being in "cold zone" beyond ecosphere, which doesn't fit later discoveries
- Written before discovery of numerous hot Jupiters by various exoplanet surveys
- Radii are physically impossible
- Alteration:
- Class I ice giant
- Class J cold gas giant
- Type 1 through 3 using Sudarsky's schema
- Class S gas dwarf
- Theoretical protoplanet state leading to ice giants, potentially also gas giant that has lost atmosphere to solar wind ablation
- Class T hot gas giant (fka hot Jupiter)
- Type 4 through 5 using Sudarsky's schema
(Star Charts unless otherwise referenced)