hypothetical planet
planet or similar body whose existence is not proven, but is speculated on by some
planet beyond Neptune
any Solar System planet that might orbit the Sun beyond Neptune
Chthonian planet
hypothetical class of celestial objects resulting from the stripping away of a gas giant's hydrogen and helium atmosphere and outer layers
Planet X
hypothetical planet in the Solar system
lava planet
type of planet with a surface primarily covered in molten lava
eyeball planet
hypothetical type of tidally locked planet with spatial features resembling an eyeball
Vulcan
hypothetical planet between the Sun and Mercury
planetary objects proposed in religion, astrology, ufology and pseudoscience
Non-scientific hypothetical planetary objects
carbon planet
extrasolar terrestrial planet
ocean planet
hypothetical type of planet whose surface is completely covered with an ocean of water with potential signs of life; in fiction see Q98807723
helium planet
A planet with a helium-dominated atmosphere
coreless planet
extrasolar terrestrial planet without a core
Phaeton
hypothetical former Solar System planet
Planet Nine
hypothetical large planet in the far outer Solar System