Class D

In the Federation standard system of planetary classification, a class D planet was characterized as a small, rock-based body, such as an asteroid or other barren, cratered planetoid with little or no atmosphere.
The planetoid known as Weytahn to the Andorians and Paan Mokar to Vulcans was an example of a class D world, though the Andorians terraformed it to have a breathable atmosphere. It was described as being not much larger than Earth's moon, Luna. ()
Regula, which in 2285 was described as a "great rock in space" with a few "unremarkable ores," was also a class D planet. () 
In 2371, the found a ringed planet in the Delta Quadrant which was also class D. Some of the asteroids comprising the rings were big enough to have class M environments inside them. ()
A subspace sinkhole encountered by the Voyager in 2375 led to a subspace pocket, where a star system composed of a G-type star and three planets was located. One of these planets was class D. It was described as hot, arid, and rocky, but otherwise had an atmosphere breathable by humanoids, e.g., Humans and Vulcans. It also supported limited indigenous plants and a species of spiders. ()
==List of class D worlds==
Image	Name 	Location 	Notes 	Source
 	Kerkhovian moon 	In orbit of Kerkhov, Vulcan system, Alpha Quadrant 	Place of origin for the Kerkhovians 	
 	Regula 	Mutara sector, near the Mutara Nebula 	 	
 	T'Khut moon 	In orbit of T'Khut, Vulcan system, Alpha Quadrant 	 	
 	Unnamed subspace sinkhole planet 	Orbiting a G-type star, inside a subspace sinkhole in the Delta Quadrant	Unusually hospitable for a class D world; destroyed when the sinkhole was collapsed by Yost in 2375	
 	Unnamed planet in the Delta Quadrant	Delta Quadrant 	Asteroids in the ring system connected to Vhnori homeworld by subspace vacuoles 	
 	Weytahn/Paan Mokar 	Andorian-Vulcan border, Alpha Quadrant 	Terraformed by the Andorian Empire in the 2050s 	
== External link ==
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