The Tau Cygna system was a star system with at least five planets in the de Laure belt. According to the provisions of the Treaty of Armens, the Sheliak Corporate could exercise a claim for this system.
In the mid-23rd century, the colony ship Artemis crash-landed on the fifth planet of this system. The survivors built a colony which lasted for nearly a century. However, under pressure from the Sheliak Corporate, the colonists were relocated to a new home. (TNG: "The Ensigns of Command")
- Tau Cygna (primary)
- Tau Cygna I
- Tau Cygna II
- Tau Cygna III
- Tau Cygna IV
- Tau Cygna V
- It is unclear whether the writers of the episode intended "Tau Cygna" to be Tau Cygni, a real binary star approximately 69 light years away from Sol. If so, this would seem to contradict the theory of Beta Lyrae ("Sheliak") actually being the Shelia system, home of the Sheliak race, as Beta Lyrae is ca. 882 lightyears from Sol, and thereby almost 13-times farther away than Tau Cygna.