Planet

A planet is a celestial body typically found in orbit around a star. Planets are typically spheroid and may have other bodies in orbit of themselves such as moons, rings or artificial satellites which can include communications or defense technology or orbital facilities such as starbases and shipyards. There are two basic types of planets: small solid rocky planets which may have a thin atmosphere, and gas giants which are almost entirely atmosphere. Small planet-like bodies are planetoids or dwarf planets. Still smaller bodies, which do not qualify to be named as planets, are asteroids.

Planetary classification[]

The Federation classified planets it cataloged based on criteria such as atmospheric composition, surface temperature, and conditions, the size of the body, and the presence of animal and plant life. This system is used to determine the suitability of the planet for exploration, colonization, and scientific research.

Each class of planet is assigned a letter in the alphabet based on its suitability. For example, Class M (sharing meaning with the Vulcan designation Minshara class) is applied to planets that can support life without any special circumstances, such as Earth, Vulcan, or Cardassia. (ST reference: Star Charts; ENT episode: "Strange New World")

The Klingons had a separate classification system, one of which is a Q'tahL class. (ENT episode: "Sleeping Dogs")

Two partially conflicting listings of planetary classification have been given by the 1989 book The Worlds of the Federation and the 2002 book Star Charts. The two sources have classes D, K and M in common, but otherwise assign classifications to conflicting letters.

Star Charts classifications[]

Class	Description	Surface	Atmosphere
Class A	geothermal	partially molten	hydrogen compounds
Class B	geomorteus	partially molten, high temperature	extremely tenuous, chemically inactive
Class C	geoinactive	low temperature	partially frozen
Class D	asteroid/moon	barren and cratered metallic, iron-nickel-silicate	none or very tenuous
Class E	geoplastic	molten, high temperature	hydrogen compounds and reactive gases
Class F	geometallic	volcanic	hydrogen compounds
Class G	geocrystalline	crystallizing	carbon dioxide, some toxic gases
Class H	desert	hot and arid, little or no water	may contain heavy gases and metal vapors
Class I	gas supergiant	tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates heat	variable pressure and composition, may contain water vapor
Class J	gas giant	tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates some heat	variable pressure and composition
Class K	adaptable	barren, little or no water	thin, mostly carbon dioxide
class L	marginal	rocky and barren, little water	oxygen/argon, high concentration of carbon dioxide
class M	terrestrial	water abundant	nitrogen, oxygen and trace elements
class N	reducing	high temperature	extremely dense, carbon dioxide and sulfides
class O	pelagic	80%+ water	nitrogen, oxygen, and trace elements
class P	glaciated	80%+ water ice	nitrogen, oxygen, and trace elements
class Q	variable	various	tenuous to dense
class R	rogue	maybe temperate due to geothermal venting	primarily volcanic outgassing
class S	ultragiant	tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates considerable heat	variable pressure and composition, may contain water vapor
class T	ultragiant	tenuous, comprised of gaseous hydrogen and hydrogen compounds, radiates considerable heat	variable pressure and composition, may contain water vapor
class Y	demon	500K+	turbulent, saturated with toxic chemicals and therionic radiation

Worlds of the Federation classifications[]

Class	Description	Surface	Atmosphere
Class A	gas giant which radiates heat; a failed star	tenuous if present	reducing, including methane
Class B	gas giant which does not radiate heat	tenuous if present	reducing
Class C	high surface temperature	iron/silicate	dense reducing
Class D	asteroid	nickel-iron/silicate	tenuous if present
Class E	large molten core	silicate, with some metals	reducing/oxidizing
Class F	less than a billion years old	silicate, with some metals	oxidizing
Class G	desert	silicate	thin oxidizing
Class H	geologically active	silicate	variable
Class I	small and young	metallic/silicate	very dense fluid
Class J	moon	silicate	tenuous, including noble gases
Class K	adaptable with pressure domes	silicate	tenuous with some water
Class L	geologically inactive	silicate/water	oxidizing
Class M	geologically active	silicate/water	oxidizing
Class N	pelagic	entirely water	oxidizing

Connections[]

multiverse • universe • galaxy
Galactic regions:	quadrant • sector • cluster • nebula • star system
System bodies:	star • planet • planetoid • dwarf planet • moon • asteroid • meteoroid • comet

For a list of planets see Planets or Planets and planetoids.

External links[]

Planet article at Memory Alpha, the wiki for canon Star Trek.
Planet article at Wikipedia, the free encyclopedia.
Standard planetary classes article at Star Fleet Universe wiki, the wiki for Star Fleet Universe / Star Fleet Battles.

Memory Beta, non-canon Star Trek Wiki