====== Helian Group ======

[[https://exoplanets.nasa.gov/resources/15/earth-and-super-earth/|{{ :worldgen:pcl:helian.jpg?nolink |Courtesy NASA/JPL-Caltech/R. Hurt (SSC)}}]]

These are rocky worlds with a mass between 5 and 17 times that of Earth. They are massive enough to retain a helium atmosphere.

===== Geo Helian Class =====

These are Helian worlds of 3 to 15 Earth masses. They lack liquids or other volatiles.
  * [[Halcyonic]] - Silicon rich worlds in tight solar orbits.
  * [[Hyperionic]] - Silicate rich with heavy volcanic activity.
  * [[Thetusean]] - Carbon rich in tight solar orbit with extensive volcanic activity.
  * [[Metusean]] - Carbon rich with volcanic activity and extensive greenhouse effect.
  * [[Solarian]] - Carbide rich close to their star.
  * [[Thean]] - Ice rich worlds beyond the snow line.


===== Nebulous Class =====

These are massive worlds with hot, dense atmospheres which support super-condensed volatiles.


===== Panthalassic Class =====

These worlds have deep oceans and thick atmospheres of water, hydrogen and oxygen. It is possible that they support life, though it will all be aquatic due to the lack of any land.