Thorne would have been a binary system if brown dwarf Mnemosyne ignited into a star.

Mnemosyne's moon Lethe lacks heavy metals, but contains rich amounts of resources for the Normandy SR-2's needs. The brown dwarf itself has a Derelict Reaper in a precarious orbit.

Derelict Reaper

Main article: Derelict Reaper

Lethe

Lethe is a moon orbiting the planet Mnemosyne.

Main article: Lethe

Mnemosyne

Mnemosyne is the first planet orbiting the star Thorne.

Main article: Mnemosyne

Trivia

• The system is likely named after Kip Thorne, one of the world's leading experts on Einstein's general theory of relativity.