Ice planet

These include most of the planetary-mass moons, such as Ganymede, Titan, Europa, Enceladus, and Triton; dwarf planets Pluto, Orcus, Haumea, Makemake, Quaoar, Sedna, Gonggong, and Eris; and the largest comets.

Many ice worlds likely have subsurface oceans, warmed by internal heat or tidal forces from another nearby body.

Liquid subsurface water would provide habitable conditions for life, including fish, plankton, and microorganisms.

Some planets, if conditions are right, may have significant atmospheres and surface liquids like Saturn's moon Titan, which could be habitable for exotic forms of life.

The largest Kuiper belt objects, such as Pluto, Haumea, Makemake, Charon, Quaoar, and Orcus[3] also qualify as such under geophysical definitions.