Titan Fleet Yards

Alpha Centauri is the closest star system to the Terran sun. The Earth colony in the Alpha Centauri system was a founding member of the Federation in 2161.

Zefram Cochrane, who lived in the Alpha Centauri system in the early 22nd century.

• Federation Member: Alpha Centauri and Proxima Centauri colonies.
• Member since: 2161
• Rationale: Star Fleet Technical Manual and later fandom assume its status as a founding member. Background material for Star Trek: Generations also included this assumption.

The Alpha Centauri system is a binary star system consisting of 2 stars that are similar to Sol. A third star, Proxima Centauri, is a red dwarf orbiting the binary system at a distance of about 0,21 lightyears. Both the binary system and the companion star support planetary systems.

The first significant mention of Alpha Centauri occured in TOS: “Metamorphosis”, where the crew meet Zefram Cochrane of Alpha Centauri. Although we later learn Cochrane was a human, at the time it may have been intended he was a native of the Centauri system. It’s generally assumed (and somewhat established in Enterprise’s “Broken Bow” and “Future Tense”) that Cochrane moved to Alpha Centauri from Earth in the early 22nd century. At any rate, it did establish Alpha Centauri as an inhabited star system with close ties to Earth and the Federation. In “Requiem for Methuselah”, the immortal Flint had some of the works of the artist Taranullus of “Centauri VII” in his collection.

Canonically, this is all we really hear about Alpha Centauri until Deep Space Nine and Enterprise. In DS9: “Past Tense”, Sisko has been invited to a dinner with Admiral Drazman of the Proxima Maintenance Yards, which we can assume is referring to the Proxima Centauri system. In the same episode, the alterations in the timeline created by the transporter malfunction cause Alpha Centauri to become part of Romulan territory. In “In the Pale Moonlight”, Alpha Centauri is listed among major worlds like Vulcan, Andor and Tellar as being threatened by the Dominion. This is the first vague hint in the television series that Alpha Centauri has any singificance as an inhabited system. In Enterprise’s “Twilight”, another alternate timeline sees the Xindi destroying a human colony in the Alpha Centauri system in the mid 22nd century. “Borderland” and “Affliction” mention as Proxima colony as well.

In newspaper clippings created for Star Trek: Generations (but ultimately never seen on screen), the “newly independent” Alpha Centuari colony signs the Federation charter in 2161.

Outside these few mentions in canon, however, Alpha Centauri has a more prominent story in fandom.

Conjectural flag and seal of Alpha Centauri colony, based on the Star Fleet Technical Manual by Franz Joseph.

In the 1975 Star Fleet Technical Manual, the Alpha Centauri Concordium of Planets is described as a founding member of the Federation. This Concordium uses a centaur and the Greek alphabet on its flag. In the 1980 Star Trek Maps, the Alpha Centauri system is described in detail: seven planets orbit the binary stars, with planets IV, V and VII inhabited. Centauri VII is home to a population of ancient Greeks, transplanted from Earth in the 3rd century BC.

This basic history of Alpha Centauri having one native humanoid (or actually human) species seems to have been respected througout the majority of fandom. Only recently, especially with the allusions to human colonies in ENT, have novels shifted towards Alpha Centauri having no native inhabitants, just Earth colonies.

In conclusion, Alpha Centauri is home to at least one inhabited planet called Centauri VII. In the late 21st or early 22nd century, a human colony was established somewhere in the system, which became a founding member of the Federation in 2161. The companion planetary system of Proxima Centauri is home to another human colony by the 22nd century, and a Starfleet shipyard in the 24th century. Possibly, Centauri VII has been home to a displaced group of humans since ancient times (of which Taranullus could have been one, I guess), but this is something I’ll leave for the reader to accept.