Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
Sirius neighboring systems
|X:Y Coordinates||-2.562 : -7.86[e]|
Sirius VI Orbital view
| Jump point
|Moons||1 (Sirius VI-a)|
|Atmospheric pressure||Thin (Breathable)|
|Highest native life||Plants|
|Ruler|| Governor: Richard Leybel|
Planetary Legate: Beverly Liktenstein
- 2167 - Terran Alliance 
- 2200 - Terran Alliance 
- 2271 - Terran Alliance 
- 2319 - Terran Hegemony 
- 2341 - Terran Hegemony 
- 2366 - Terran Hegemony 
- 2571 - Terran Hegemony 
- 2596 - Terran Hegemony 
- 2750 - Terran Hegemony 
- 2765 - Terran Hegemony 
- 2767 - Amaris Empire 
- 2771 - Amaris Empire 
- 2774 - Amaris Empire 
- 2786 - Terran Hegemony 
- 2822 - Free Worlds League 
- 2864 - Free Worlds League 
- 2901 - Free Worlds League 
- 3025 - Capellan Confederation 
- 3029 - Tikonov Free Republic (from March)
- 3030 - Tikonov Free Republic 
- 3040 - Federated Commonwealth 
- 3050 - Federated Commonwealth 
- 3052 - Federated Commonwealth 
- 3057 - Federated Commonwealth 
- 3058 - Chaos March 
- 3062 - Free Worlds League 
- 3063 - Free Worlds League 
- 3067 - Free Worlds League 
- 3072 - Word of Blake Protectorate
- 3130 - Republic of the Sphere 
- 3145 - Republic of the Sphere 
The main star of the Sirius system (Sirius A) has a white dwarf companion (Sirius B) on an elongated orbit that brings it to within nearly 10 AU of the primary roughly every 50 years, with such close passages in 2993.
The planet Sirius V has a chill, subzero hydrogen-methane atmosphere that makes for a yellow-green sky. Red mud and ice-rimmed pools of liquid ammonia are mentioned. The surface temperature rarely raises beyond -40 centigrade, and the gravity is 1.5g; the planet was settled almost a century after the research station on Sirius VI-a, to exploit its considerable resources of heavy metals and transuranic minerals.
The first settlements on Sirius were actually on Sirius VI-a, the moon of the last planet, as it had a breathable atmosphere. It wasn't until around fifty years later that the resource-rich but oxygen-poor planet Sirius VI was colonized. Throughout the Succession Wars, the terraforming that allowed the settlement of Sirius VI was slowly reversed, until the only habitable area was the domed city of Calgary. The capital city of Sirius VI-a, Lost Hope, was located on the Bounty continent, one of two main continents on the moon. Bounty and the other major continent, Hinterlands, would become home to the bulk of the population in the Sirius system.
Terran Alliance explorer Alana Korvin DeVall founded the Sirius colony in 2167. Upon its discovery, Sirius was considered a poor colonization candidate, due to its hostile atmosphere and frequent seismic activity, but its vast mineral wealth encouraged the adventurous (and desperate) to seek a profit. In 2200, the major mining corporations finally decided to move in, and began terraforming Sirius with oxygen factories and sulfur-eating algae. Sirius was one of the systems that remained a part of the Terran Alliance following the Outer Reaches Rebellion and the Demarcation Declaration of 2242, and became one of the worlds within the Alliance Core region of the Terran Hegemony.
By 2300, the atmosphere had become breathable, and Seismic Suppressor Stations were constructed, designed to sense an approaching earthquake and prevent it through underground explosives. Despite this use of advanced Hegemonic technology, surface disruptions prevented the construction of any terrestrial manufacturing centers. Instead, orbital factories were constructed, along with twin habitation colonies known as "The Projects." Each station could house 10,000 workers in Terra-like comfort. Whilst Sirius VI continued to be plagued with chronic earthquakes and volcanic activity and remained a water-poor world, the mining colonists on Sirius VI and the settlers on Sirius VI-a developed a symboitic relationship, and travel between the two dwarfed the traffic with other systems in terms of frequency. The Projects were an interesting waypoint for those traveling between the two.
During the Amaris Civil War, the Rim Worlds Republic destroyed The Projects without reason, killing 8,000 colonists. A further 9,000 were killed on the planet's surface when Republican forces stripped the planet of its resources and prevented the shipping of any further supplies. The blockade resulted in widespread starvation on Sirius VI.
Succession Wars eraEdit
After the fall of the Star League, the planet fell under the control of the Capellan Confederation, but lacking the Hegemony's technological know-how, the oxygen factories have since started to fail, forcing much of the population to evacuate the planet. Many of the planetary settlements on Sirius VI were torn apart by seismic activity, and conditions on the planet steadily worsened; control of the Sirius system was fought over by the Confederation, the Free Worlds League and later the Federated Commonwealth.
Third Succession WarEdit
Sirius V was raided by the Gray Death Legion (in the employ of House Marik and the Free Worlds League) in late 3027. Following the surrender of the capital city of Tiantan, rogue elements posing as the Gray Death Legion detonated demolition charges at the city's domes and marched BattleMechs through the ruins, killing some 17 million inhabitants with the intent of blaming the atrocity on the Gray Death Legion. It would later be revealed that a conspiracy involving rogue ComStar Precentor Emilio Rachan and Lord Garth of Irian was behind the act.
Fourth Succession WarEdit
Following negotiations between Colonel Pavel Ridzik, chief military advisor to Chancellor Maximillian Liao, and AFFS Lieutenant General Ardan Sortek, conducted in February 3029 Ridzik created a new nation, the Tikonov Free Republic. The Republic was created by incorporating those worlds of the Tikonov Commonality that hadn't already been conquered during the first half of the Fourth Succession War. Ridzik returned to Elgin, the new capital of the Tikonov Free Republic, on the 3rd of March 3029 and swiftly began implementing a new government consisting of family members, friends and other appointees loyal to himself, purging dissident elements on the various Republic worlds and taking the opportunity to settle old scores. Sirius was one of the systems incorporated into the Republic.
FedCom Civil WarEdit
By the end of the FedCom Civil War and the demise of the Federated Commonwealth Sirius VI had been rendered almost completely uninhabited, the world having become a wasteland of a broken, shifting landscape intercut with rivers of volcanic lava.
During the third week of June 3069 the worlds of Berenson, Irian, Procyon and Sirius were rocked by internal conflict as Free Worlds League Loyalists clashed with local government forces as a result of the local governments turning against the false Thomas Marik and the government on Atreus.
The Dark AgeEdit
The Sirius system was incorporated into the Republic of the Sphere; the bulk of the population in the system lived on Sirius VI-a, scattered in small farming communities across the two major continents. Calgary remained the last population center on Sirius VI, huddled on the banks of the Sulfur Sea.
- Lothar's Fusiliers (2nd Battalion)
- Third Confederation Reserve Cavalry (First Battalion)
- Justine's Grenadiers (2nd Battalion)
- Kerr's Intruders (3rd Battalion)
3059 to 3067Edit
| Systems within 60 light-years (distance in light years)|
Closest systems first:
|New Home||14.7||Carver V||15.7||New Earth||20.8||Bryant||21.1|
|Caph||22.8||Graham IV||23.5||Killbourn||23.5||Alula Australis||24.9|
|Devil's Rock||41.1||Denebola||41.5||Northwind||41.7||Imbros III||42.4|
- The planet Sirius is misspelled in the ComStar (sourcebook) as Siris.
- Dark Age: Republic Worlds (3130), p. 250, "Sirius"
- The Star League, p. 177
- Handbook: House Marik, p. 16, "Free Worlds League Founding ["
- Handbook: House Kurita, p. 18, "Draconis Combine Founding - 2319"
- Handbook: House Steiner, p. 13, "Lyran Commonwealth Founding "
- Handbook: House Liao, p. 17, "Capellan Confederation Foundation "
- Handbook: Major Periphery States, p. 18, "Rim Worlds Republic after Age of War "
- Handbook: House Steiner, p. 25, "Lyran Commonwealth after Age of War "
- Historical: Reunification War, p. 159, "Inner Sphere - 2596"
- Era Report: 2750, p. 37, "Inner Sphere - 2750"
- Historical: Liberation of Terra Volume 1, p. 11, "Inner Sphere - 2765"
- Historical: Liberation of Terra Volume 1, p. 84-85, "Atrocities And Excesses"
- Historical: Liberation of Terra Volume 1, p. 104, "Rim Worlds Republic -  Map"
- Historical: Liberation of Terra Volume 1, p. 138, "Operation LIBERATION Wave 1 [July 2772 - December 2774]"
- First Succession War (Source Book), pp. 24-25, "Inner Sphere -  Map"
- Handbook: House Marik, p. 34, "Free Worlds League after First Succession War "
- First Succession War (Source Book), pp. 112-113, "Inner Sphere -  Map"
- Handbook: House Marik, p. 38, "Free Worlds League after Second Succession War "
- House Marik (The Free Worlds League), p. 90, "Marik Militia"
- House Liao (The Capellan Confederation), p. 105 - "Unit Deployment Table"
- NAIS The Fourth Succession War Military Atlas Volume 2, p. 16-17, "Tikonov Free Republic"
- NAIS The Fourth Succession War Military Atlas Volume 2, p. 16, "Tikonov Commonality (Map)"
- NAIS The Fourth Succession War Military Atlas Volume 2, p. 94, "End Of The War"
- Historical: War of 3039, p. 133, "Inner Sphere - 3040"
- Era Report: 3052, p. 11, "Inner Sphere - 3050"
- Era Report: 3052, p. 23, "Inner Sphere - April 3052"
- Era Report: 3062, p. 11, "Inner Sphere - August 3057"
- Handbook: House Liao, p. 60, "Capellan Confederation after Operation Guerrero -  Map"
- Era Report: 3062, p. 29, "Inner Sphere - July 3063"
- Field Manual: Updates, p. 159 - "Fre Worlds League Deployment Table"
- Handbook: House Liao, p. 68, "Capellan Confederation after FedCom Civil War -  Map"
- Jihad: Final Reckoning, p. 43, "Inner Sphere -  Map"
- Map of the Inner Sphere 3130
- Inner Sphere - 3145
- The Price of Glory (PDF Edition), pp. 5 - 10
- House Liao (The Capellan Confederation), p. 64
- The Price of Glory, p. 119
- According to the Gray Death Legion scenario pack, p. 33, the Gray Death Legion made landfall on Helm on 24 March 3028 after a hasty trip from Sirius V. Given the travel time to Sirius V's jump point, the distance between the Sirius and Helm systems which requires at least five jumps, and the travel time from Helm's jump point to the planet indicates that the Gray Death Legion must have left Sirius V sometime in late 3027.
- The Price of Glory
- Jihad: Final Reckoning, p. 47, "The Jihad In Review"
- First Succession War (Source Book), p. 138, "First Succession War Deployment Table - FWLM"
- House Liao (The Capellan Confederation), p. 106 - "Unit Deployment Table"
- ComStar (sourcebook), p. 84, "Com Guards Deployment Table"
- 'ComStar (sourcebook), p. 85'
- Field Manual: Free Worlds League, p. 110 - "Free Worlds League Deployment Table"
- Field Manual: Free Worlds League, p. 113 - "Free Worlds League Deployment Table"
- Field Manual: Updates, p. 161 - "Free Worlds League Deployment Table"
- Field Manual: Updates, p. 160 - "Free Worlds League Deployment Table"
- Field Report: Clans, p. 15, "Clan Jade Falcon Deployment Status"
- Field Manual: 3145, p. 145, "Republic Armed Forces - Triarii Protectors"
- First Succession War, p. 125, "Shipbuilding Casualties of the First Succession War"
- Experimental Technical Readout: Primitives, Volume 5, p. 10, "Asher Hover Scout"
- ComStar (sourcebook)
- Dark Age: Republic Worlds (3130)
- Era Report: 2750
- Era Report: 3052
- Era Report: 3062
- Era Report: 3145
- Experimental Technical Readout: Primitives, Volume 5
- Field Manual: 3145
- Field Manual: Free Worlds League
- Field Manual: Updates
- Field Report: Clans
- First Succession War
- Handbook: House Kurita
- Handbook: House Liao
- Handbook: House Marik
- Handbook: House Steiner
- Historical: Liberation of Terra Volume 1
- Historical: Reunification War
- Historical: War of 3039
- House Liao (The Capellan Confederation)
- House Marik (The Free Worlds League)
- The Price of Glory
- Jihad: Final Reckoning
- Map of the Inner Sphere 3130
- NAIS The Fourth Succession War Military Atlas Volume 2
- The Star League