Planetary and Stellar classes

The following information is gathered from various sources, including NASA documents, The original FASA Star Trek RPG, Memory Alpha (where it does not flagrantly disagree with otherwise established classes), and various other sources.

List of known classes

Class	Surface	Atmosphere	Description	Example
A	tenuous, may not be present	reducing; methane, etc.	radiates heat, "failed" star	Jupiter, Saturn
B	tenuous, may not be present	reducing	non-radiant	Neptune
C	iron/silicate	reducing/dense	high surface temperature	Venus
D	nickel-iron/silicate	(A-G)none, (H-N)tenuous	asteroids	Ceres
E	silicate, some metals	reducing/oxidizing	large molten core	Janus IV
F	silicate, some metals	oxidizing	very young	Delta Vega
G	silicate	oxidizing, thin	desert planet	Rigel XII
H	silicate	variable	geologically active	Gothos
I	metallic/silicate	fluid, very dense	small/young	Excalibis
J	silicate	very tenuous, noble gasses	moons	Luna
K	silicate	tenuous, some water	adaptable with pressure domes	Mars
L	silicate/water	oxidizing	geologically inactive	Psi 2000
M	silicate/water	oxidizing	geologically active	Terra
N	water entirely	oxidizing	pelagic planet	Argo
P	water/silicate	oxidizing	glacial planet	Breen
R	water/silicate	negligible	Rogue	Dakala
S	small dense metallic	reducing	small ultra gas giant	Braxis
T	small dense nickel-iron	reducing	large ultra gas giant	Luava
Y	metallic/silicate	reducing	demon class	Silver Blood planet