Sirius system

The Sirius system was a binary star system located in Mutter's Spiral. The system had been the home to many sentient species during its history, including humans, Varlons, and Quagreegs, although only limited knowledge of interaction between these species is known.

Astronomical data
The binary stars known as Sirius were located at the centre of the system. (TV: The Curse of the Black Spot)

Planets in the Sirius system included Sirius Alpha, (AUDIO: Max Warp) Androzani Major and Minor, (TV: The Caves of Androzani) Sirius IV, (TV: Frontier in Space) Sirius 5, (TV: City of Death) Sirius 7, (AUDIO: The Soers' Ditch) and Quagreeg. (AUDIO: Dead London)

History
Humans from different time periods in London, at least between the 1st century and 2008, were kidnapped by a Quagreeg called Sepulchre, and imprisoned within reenactment chambers in his mind. Quagreegs are the eponymous natives of their planet in the Sirius system. (AUDIO: Dead London)

During at least one point between 2068 and 2096, (TV: Nightmare of Eden) the Sirius system was a part of the Varlon Empire. The Sirius Exhibition Station was based there. During this time the Eighth Doctor and Lucie Miller visited and became embroiled in a murder investigation. (AUDIO: Max Warp)

By the time of the Earth Empire, the Sirius system had been colonised by humans. However, by 2540, Sirius IV was an independent dominion planet. (TV: Frontier in Space)

By the 51st century, (PROSE: Diamond Dogs) the Sirius Conglomerate was a major power in the system, involved in activities on the planet Androzani Major, which held reserves of spectrox, a substance conferring longevity. (TV: The Caves of Androzani)

Undated events
There was apparently an art gallery on Sirius 5 that Romana thought could rival The Louvre. (TV: City of Death)

The Doctor once visited Sirius IV in or prior to their sixth incarnation. (AUDIO: Pier Pressure)