Definition
Netherion are icy dwarf planets located at the edges of stellar systems, often beyond the gas giants. Their surface is mainly composed of methane (CH₄), nitrogen (N₂), and carbon monoxide (CO) ices, forming dense layers at very low temperatures.
Surface and Atmosphere
Their surface undergoes cycles of freezing and sublimation linked to their eccentric orbits. When they approach their star, the ices pass directly into a gaseous state and form a thin and temporary atmosphere, which later redeposits as the object moves away again. This dynamic produces a pronounced and unstable seasonal cycle.
Orbits
Netherion follow elliptical and inclined orbits, sometimes unstable, which may intersect with those of other bodies. These trajectories are often influenced by the gravitational resonances of giant planets. Their very long orbital period makes their evolution slow and difficult to observe in short timescales.
Composition and Structure
The icy crust contains simple organic compounds that record the original chemical conditions of the protoplanetary disk. These dwarf planets preserve materials little altered by radiation or collisions.
Role in Planetary Evolution
As trans-Neptunian objects, Netherion play an important role in the study of planetary system formation. Their distribution and composition provide clues about the processes of planetary growth, gas giant migration, and the organization of outer regions.