Mnemosyne is a brown dwarf of approximately 37 Jupiter-masses. It is young enough that some nuclear fusion still occurs within its depths. It is luminous, and radiates more heat than it receives from the star Thorne, with an atmospheric temperature in excess of 1,800 degrees Kelvin (1,500 degrees Celsius).
Early probes of Thorne showed evidence of a minor gravitic anomaly in the northern hemisphere. This area of unexpectedly low mass did not move with the prevailing wind patterns. While an investigation was planned by the Besaral Institute of Planetary Science, the school ultimately sent an expedition to study the famed "deep anomalies" of the gas giant Ploba instead.