Proxima Centauri, also known as Alpha Centauri C, was a planetary system. This system consisted of a primary and at least one planet. The Proxima Centauri system had at least one planet that was suitable for colonization by humanoid life-forms. This star was located in close proximity to the Alpha Centauri system. Both systems were located in the Alpha Quadrant. This binary star system had its own planetary system. Other nearby stars were Sirius, Sol, and Tau Ceti. (Star Trek VI: The Undiscovered Country, production art; TNG: "The Naked Now", ENT: "Borderland")
The Proxima colony, an Earth colony, was founded on this planet prior to 2154. In that year, a Klingon warship was spotted near this colony. The incident was reported in an intelligent file that Captain Jonathan Archer received. Admiral Maxwell Forrest believed that the Klingons were conducting a reconnaissance scan for a future strike. (ENT: "Borderland")
Later that year, a Rigelian freighter departed Earth two hours after Doctor Phlox was abducted. According to a filed flight plan, the freighter's destination was the Proxima colony. However, the trajectory of this freighter wouldn't take it anywhere near the colony. Upon coming to this conclusion, Captain Archer cancelled shore leave. Soon afterwards, his ship, the Enterprise, was in pursuit of the freighter. (ENT: "Affliction")
In the 24th century, Proxima Centauri was home to Starfleet's Proxima Maintenance Yards. Under the command of Admiral Drazman in 2371, Commander Benjamin Sisko, Doctor Julian Bashir and Lt. Jadzia Dax planned to visit the Yards in that year. (DS9: "Past Tense, Part I"). The Proxima colony was, also, home to the Proxima Centauri Interplanetary Bowling League. (TNG: "The Schizoid Man")
|Alpha Centauri system|
|Alpha Centauri A • Alpha Centauri B • Proxima Centauri|
|Centauri VII • Proxima colony|
In a scene apparently cut from TOS: "Wolf in the Fold", a reference was made to Alpha Proxima II, that was later replaced in the dialog, but survived in numerous subsequent references. It was likely, if indeed this planet existed as it appears to have intended to in the original reference, it would have been the location of yet another colony, or possibly an alternate name for the Proxima colony.
Alpha Centauri was misspelled as "Alpha Centuri" in the "The Explored Galaxy" star chart graphic seen in "Star Trek: The Undiscovered Country". "The Explored Galaxy" was a map of charted space in the Alpha Quadrant. This system was located between the Tholian Assembly and Romulus. Both locations were identified in DS9: "The Search, Part II", "Call to Arms" as being located in the Alpha Quadrant. This chart was also seen in several Star Trek: The Next Generation and Star Trek: Deep Space Nine episodes set in the 24th century, from the year 2364 to 2370. These were: TNG: "Conspiracy", "The Measure Of A Man", "The Emissary", "The Mind's Eye", "The Game" and DS9: "In the Hands of the Prophets", "Cardassians".
This chart naming stars within 20 light years of Sol was drawn by Rick Sternbach for the Star Trek Spaceflight Chronology in the late 1970s. Found on page 77, this chart showed Earth commercial and exploration routes after the use of warp drive began. There were no commercial or exploration routes to Alpha Centauri C. This chart would later appear in the episodes "The Last Outpost" and "Conspiracy".