Planetary classification

Planetary classification systems were used by many races to categorize planets. Various factors were taken into consideration, including atmospheric composition, surface temperature, vegetation and size. The classification system used by the Federation used single-letter designations, for example class M to describe a planet able to support humanoid life for long periods, while the Vulcans used the term "Minshara class" to describe a similar planet.

Planetary classes

Class	Description	Examples
Class D	Planetoid or moon; uninhabitable	Paan Mokar, Regula
Class H	Generally uninhabitable	Tau Cygna V
Class J	Gas giant	Jupiter, Saturn
Class K	Adaptable with pressure domes	Mudd, Theta 116 VIII (class K transjovian)
Class L	Marginally habitable	Indri VIII
Class M	Terrestrial	Earth, Risa, Bajor
Class N	Sulfuric	Venus
Class T	Gas giant
Class Y	"Demon"	Silver Blood planet

Generally, the further away from Class M a planet is, the less habitable it is likely to be for humans (and similar life forms), i.e. Class L are cold planets with only plant life but breathable atmospheres, Class K planets have tolerable gravity but not breathable atmospheres and require pressure domes for habitation, Class D planet have no atmospheres, and Class Y are considered utterly inhospitable toxic environments. However, an official underlying scheme for planetary classification has not been revealed, leaving the possibility that the letter designations simply stand for terms (i.e. "M" for the Vulcan term "Minshara"), and that there is no intended pattern corresponding to how close to "M" the designation is in the alphabet.

Background

The Star Trek: Star Charts book, which was authored and advised by Trek staffers, listed many other planetary classes which may one day be recognized on-screen, but as of now they remain conjectural.

One such was "Class F", which was geologically inactive with no atmosphere. Janus VI was given as an example of this.

According to the Star Charts, a Class P planet is a "glaciated" planet. They have an age that ranges from three to ten billion years and a diameter between 10,000 to 15,000 kilometers. Class P planets are located in the ecosphere of a solar system. A glaciated planet is categorized by a surface comprised of 80%+ water ice and an atmosphere consisting of nitrogen, oxygen and trace elements. Lifeforms found on class P planets include hardy vegetation, animal life, and occasionally native humanoids. It is widely believed that Breen is also a class P planet. However, according to Weyoun, it was in fact a lush world with a temperate climate, in which case it would have to be categorized as class M. (DS9: "When It Rains...")

Examples of class P planets:

• Andor
• Exo III
• Rigel X
• Psi 2000

External link

• Template:Exastris