Neptunian exoplanets are a class of exoplanets that are similar in size to the ice giants Neptune and Uranus in the Solar System. Neptunian exoplanets may have a mixture of interiors though all would be rocky with heavier metals at their cores. Neptunian planets typically have hydrogen- and helium-dominated atmospheres.
There are several recognized subtypes of Neptunian exoplanets:
- Hot Neptune â orbiting close to its star
- Helium planet â a hypothetical type that can form from hot Neptune via hydrogen evaporation, leaving a helium-dominated atmosphere
- Mini-Neptune â considerably smaller than Neptune but still having a thick hydrogen-helium envelope, relatively common
- Super-puff â inflated planets with unusually low mean density
- Hycean planet â a hypothetical transitional type to ocean planets with a thin, hydrogen-helium-dominated atmosphere overlaying a liquid water ocean
List of Neptunian exoplanets
Kepler
GJ
TOI
LTT
HAT
OGLE
Other
References