The Unknown Solar System appears in Metroid Prime 3: Corruption, and is where the Pirate Homeworld is located. After Samus Aran cleanses Elysia of its Leviathan, Aurora Unit 242 informs her that a communication capsule has revealed the location of the Pirate Homeworld Seed. This also confirms the location of the Pirate Homeworld, and Samus is tasked with infiltrating the planet to destroy the seed and enable a full-scale assault on the Space Pirates.
The Solar System also holds the Leviathan Battleship in orbit around the homeworld and later, the G.F.S. Olympus, when the time comes to open the wormhole to Phaaze. Beyond this, little is known of what is contained in the Unknown Solar System.
Federation Solar System | Gaflar System | Kalandor region | Messina System | Extreme Galaxy
Milky Way Galaxy | Small star | SR388's solar system | Sun | Tetra Galaxy | Unknown Solar System