Sirius (also known as Alpha Canis Majoris, Alpha Canaris or the Alpha system) is a binary star system in Federation space consisting of companion stars named Sirius A and Shahr, located about 2.6 parsecs (8.6 light years) from Earth, where it is visible in the constellation of Canis Major. It is the location of the planet Alpha III, an important Federation colony. (TOS references: Star Fleet Technical Manual, Spaceflight Chronology)
In the field of stellar cartography, Sirius is a landmark that was used in the naming of the Sirius sector block. Sirius is not located in the Sirius sector block, but rather in the neighboring Alpha Trianguli sector block. (STO video game: Star Trek Online)
The Dogon of Mali are believed to have been visited thousands of years ago by aliens from Sirius. In 1940, Benny Russell had a vision where a Dogon encountered one of the aliens who died soon after. (DS9 novelization: Far Beyond the Stars)
- The Dogon people are believed to have known of the existence of Sirius and its companion star.
On several occasions in 2364, viewscreen readouts aboard the USS Enterprise-D showed the location of Sirius, in the form of charts from the Enterprise library computer. (TNG episodes: "The Naked Now", "The Last Outpost", "Conspiracy"
- Alpha I
- Has no atmosphere, and is geologically dead. An asteroid belt separates it from Alpha II.
- Alpha II
- Has a highly poisonous atmosphere and is very geologically active.
- Alpha III
- Has 7 moons. Another asteroid belt separates Alpha III from the trojan planet system of Alpha IV and V.
- Sirius IV
- Gas giant, has 12 moons
- Alpha V
- Has 29 moons. Alpha IV and V are gas giants that slowly revolve around each others as they orbit the star system.
- Centauran colony.
The Chronology depicted Sirius's name and distance from Earth on star chart illustrations, but since it is a "real" star system, modern scientists know a few things about its makeup that weren't in its Star Trek mentions.
It is notable that Sirius was briefly glimpsed onscreen in canon productions of Star Trek because the production staff copied their star charts from the earlier, non-canon Chronology. In close proximity to Earth, Sirius is in the vicinity of sector 006 and is therefore a Beta Quadrant star system, directly on the edge of the Alpha Quadrant. FASA RPG module: The Federation claims this system contains two Class M worlds but doesn't identify the other world.
Star Trek Online suggests that the planet Vulcan is located in the Sirius system. A location at Sirius would be a contradiction of canon since ENT episode: "Home" states it is 16 light-years from Earth. Other sources generally agree the Vulcan system exists around the triple star 40 Eridani.
In modern day astronomical notation, the two stars of Sirius do not have separate names, particularly the secondary's name "Shahr", which appears to have been devised for the Technical Manual.
|Stars, systems and objects of the Canis Major constellation|
|Alpha Canis Majoris (Sirius, Alpha Canaris: Sirius A • Shahr) • Delta Canis Majoris (Wezen, Delta Canaris) • Epsilon Canis Majoris (Adhara, Epsilon Canaris) • Gamma Canis Majoris (Muliphen, Gamma Canaris) • Pi Canis Majoris (Korvat, Pi Canaris)|
|Alpha Trianguli sector block|
|Algira sector||Alpha Majoris (Alpha Majoris I) • Sirius system (Sirius A, Shahr: Alpha I • Alpha II • Alpha III • Sirius IV • Alpha V • Springboard) • Lilsis|
|Almatha sector||Almatha system • Aria system • Caralun system • Corwin system • Santos system • Trivas system|
|Dorvan sector||Aokii system • Dorvan system (Dorvan V) • Andoss system • Minas Korva system • Obrom system|