The class H-planet Tau Cygna V
In the Federation standard system of planetary classification, a class H planet was characterized as usually being uninhabitable by Humans. In the Treaty of Armens, "unwanted lifeforms inhabiting H class worlds may be removed at the discretion of the Sheliak Corporate." (TNG: "The Ensigns of Command")
An H class planet or moon could contain an atmosphere consisting of Oxygen and Argon. (VOY: "Scorpion, Part II")
Examples of a Class H planets:
| Planetary classification |
|---|
| B • D • G • H • J • K • L • M • N • R • T • Y • Other classes |
Appendices
Background information
According to the Star Trek: Star Charts, Class H worlds have an age of 4-10 billion years and have a diameter ranging from 8,000 to 15,000 km. They are found throughout a solar system. A 'Desert' planet is categorized by a hot and arid surface, with little or no surface water and an atmosphere that may contain heavy gasses and metal vapors. Lifeforms found on Class H planets include drought and radiation-resistant plantlife and similar animal life.
Because they are also arid planets, Ocampa, Nimbus III, Rigel XII and Ceti Alpha V (as of 2268) could also be H class planets, but they were never identified as such.