Sirius 3151.svg
System Information
X:Y Coordinates-2.562 : -7.86[e]
Spectral classA1V[1]
Recharge station(s)Zenith (3058)[2]

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.

System Description[edit]

Sirius is located near the Procyon and Keid systems.

Political Affiliation[edit]

Sirius V[edit]

Sirius V
System positionFifth[43]
Surface gravity1.5[43]
Highest native lifeNone[43]
Government and Infrastructure

The planet Sirius V has a chill, subzero hydrogen-methane atmosphere that makes for a yellow-green sky.[44] Red mud and ice-rimmed pools of liquid ammonia are mentioned.[44] 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.[44]

Planetary History[edit]

Tiantan massacre[edit]

Sirius V was raided by the Gray Death Legion (in the employ of the Free Worlds League) in late 3027.[45] 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 seventeen 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.[46]

Sirius VI[edit]

Sirius VI
System positionSixth[1]
Jump Point distance47 days[1][3]
Moons1 (Sirius VI-a)[1]
Surface gravity0.86[1]
Atmospheric pressureThin (Breathable)[1]
Equatorial temperature33°C[1]
Surface water16%[1]
Highest native lifePlants[1]
History and Culture
Population700,000 (2766),[3]
20,000 (3025),[3]
9,109,000 (3130)[1]
Government and Infrastructure
Political LeaderPlanetary Governor
Military CommanderLegate Beverly Liktenstein (3130)[1][47]
Sirius VI-a
Atmospheric pressureThin (Breathable)[1]
Surface waterLess than 50%[1]
Landmasses2 (Bounty, Hinterlands)[1]
History and Culture
ColonizedEarly 2100s
Government and Infrastructure
CapitalLost Hope[1]

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.[1]

Planetary History[edit]

Early History[edit]

Terran Alliance explorer Alana Korvin DeVall founded the Sirius colony in 2167.[3][48] 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.[3] 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,[4] and became one of the worlds within the Alliance Core region of the Terran Hegemony.[10]

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.[3] 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 symbiotic 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.[1] The Capellan Confederation captured the Sirius system in 2370, along with the neighboring Procyon system.[2]

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.[3] The blockade resulted in widespread starvation on Sirius VI.[1]

First Succession Wars[edit]

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.[3] 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.[1]

Third Succession War[edit]

In 2901, the Tenth and Fourteenth Marik Militias were responsible for conquering Sirius for the Free Worlds League.[24]

As of ca. late 3027, Sirius was described as a "fairly important world on Liao trade lanes."[49]

Fourth Succession War[edit]

Following negotiations between Colonel Pavel Ridzik, chief military advisor to Chancellor Maximilian 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 3 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.[27]

Operation GUERRERO[edit]

The Sirius system wasn't a target of the Operation GUERRERO campaign launched by the Free Worlds League, but on 24 October 3057 the local HPG transmitter was seized by an unidentified faction. Approximately two months later, JumpShips entering either the Sirius or Procyon systems began being challenged by transmissions declaring that they had entered the Sirian Holds, and were ordered to leave or face destruction. This continued for some time, with at least two independent trading ships being reported missing. The Free Worlds League made multiple attempts to open up diplomatic communications with either system, but all such efforts went unanswered, as did efforts by ComStar to initiate contact, although observations indicated that the two systems were exchanging HPG transmissions with each other. Reports indicated that the planetary government on Sirius had recently contracted a mercenary unit named Jo's Fourth Cavalry prior to the formation of the Sirian Holds.[2]

It was some time before the mystery around the Sirian Holds was solved; both Sirius and Procyon had been taken over by the supporters of a charismatic former ComStar acolyte named Alisendar Gyrn. Gyrn was a member of an ancient trading family from Sirius, and had fallen prey to delusions years before that led him to believe he was the reincarnation of Jerome Blake. Under the thrall of these delusions, Gyrn had spent years recruiting devoted followers in both systems, and he seized on the disruption caused by Operation GUERRERO to lead his followers in an uprising. Gyrn seized both HPG stations, and used assassins to kill key officers in Jo's Fourth Cavalry and Boodelay's Backup, the mercenary force employed by the planetary government on Procyon. Followers of Gyrn who had infiltrated the support staffs of both mercenary units were responsible for sabotaging key equipment, such as the mercenary commands' JumpShips, and Gyrn had the supplies to both units cut off. Many of the mercenaries attempted to contest Gyrn's actions, but were unsuccessful when they tried to depose Gyrn, and the survivors were forced to retreat into the wilderness.[50]

With the HPGs under his control and the local mercenary forces neutralized, Gyrn's rule over the newly formed Sirian Holds was announced by his loyal followers to the stunned populations of both systems. No mention was made at first of the alleged divinity of Alisendar Gyrn; instead, the takeover was pitched as freeing the systems from the Great Houses, and there was relatively little protest from the population, at least at first. When word reached the wider population of what had happened to the mercenary troops, along with the discovery that Gyrn was in control of the HPG systems, protests broke out. As the protests accelerated towards becoming an open revolt, Gyrn announced that both systems needed to be "purified"; this purification consisted of destroying all modern technology. Gyrn's followers rounded up intellectuals, technicians, dissenters and various other groups, with the roundups being described as the beginning of a process of reeducation; instead, those gathered up were murdered in killing fields outside the capital city, to prevent them posing any kind of threat to Gyrn.[50]

Subsequently believed to be a renegade Blakist, Gyrn's hellish regime fell in early 3059, when Free Worlds League Military forces captured Procyon and Sirius and returned them to League rule.[51]

FedCom Civil War[edit]

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.[1]


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.[52]

The Dark Age[edit]

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.[1]

Military Deployment[edit]


Sirius VI-a, the moon of Sirius VI, has two continents named Bounty and Hinterlands.[1]

Planetary Locations[edit]

  • Calgary: the only remaining domed city on Sirius VI, on the south bank of the Sulfur Sea[1]
  • Lost Hope: the capital city of the moon Sirius VI-a[1]
  • Sulfur Sea: the planet's only large body of water[1]

Companies and Industries[edit]


  • The system is misspelled in the ComStar sourcebook as Siris.[55]

Map Gallery[edit]

Nearby Systems[edit]

Closest 80 systems (80 within 60 light-years)
Distance in light years, closest systems first:
Procyon 4.1 Keid 6.1 Sol 8.3 Rigil Kentarus 10.4
New Home 10.9 Carver 13.2 Tau Ceti 14.7 Bryant 16.6
Caph 17.1 Graham 21.1 Killbourn 21.1 Xi Ursae Majoris 22.0
Hechnar 23.1 Brownsville 23.7 Altair 24.4 Epsilon Eridani 24.8
New Stevens 25.0 Thorin 26.3 Outreach 26.8 Fomalhaut 27.0
Dieron 27.1 Oliver 29.3 Yorii 29.5 Pollux 30.0
Zavijava 30.2 Chara 30.2 Epsilon Indi 32.7 Muphrid 33.9
Asta 34.1 Saffel 34.4 Lipton 34.4 Devil's Rock 34.4
Capolla 35.2 Rocky 35.5 Denebola 35.8 Terra Firma 35.9
Tabit 36.8 Northwind 37.0 Zollikofen 37.9 Hall 38.1
Castor 38.9 Talitha 41.4 Imbros 41.9 Chisholm 43.3
Athenry 43.7 Styx 43.8 Lockdale 44.1 Van Diemen 45.4
Sheratan 45.5 Nirasaki 45.9 Haddings 46.8 Menkent 47.2
Hsien 47.2 Zosma 47.7 Mandal 48.5 Afleir 49.0
Dyev 49.4 Wasat 49.8 Nanking 50.7 Lyons 50.9
Bex 51.7 Fletcher 51.8 Acamar 52.1 Pike 52.3
Quentin 52.6 Ingress 53.3 Summer 53.9 Ko 54.0
Small World 54.3 Woodstock 55.0 Deneb Algedi 55.3 New Dallas 55.3
New Britain 55.5 Errai 56.2 Marcus 56.9 Chaville 58.3
Lone Star 58.3 Tall Trees 59.0 Mizar 59.3 Zurich 59.8


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 Dark Age: Republic Worlds (3130), p. 250: "Sirius"
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Chaos March, p. 22: "Sirian Holds"
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 The Star League, p. 177: "Sirius" planet profile
  4. 4.0 4.1 Handbook: House Marik, p. 16: "Free Worlds League Founding [2271]"
  5. Handbook: House Kurita, p. 18: "Draconis Combine Founding - 2319"
  6. Handbook: House Steiner, p. 13: "Lyran Commonwealth Founding [2341]"
  7. Handbook: House Liao, p. 17: "Capellan Confederation Foundation [2366]"
  8. Handbook: Major Periphery States, p. 18: "Rim Worlds Republic after Age of War [2571]"
  9. Handbook: House Steiner, p. 25: "Lyran Commonwealth after Age of War [2571]"
  10. 10.0 10.1 Historical: Reunification War, p. 159: "Inner Sphere - 2596"
  11. Era Report: 2750, p. 37: "Inner Sphere - 2750"
  12. Historical: Liberation of Terra Volume 1, p. 11: "Inner Sphere - 2765"
  13. Historical: Liberation of Terra Volume 1, pp. 84–85: "Atrocities and Excesses"
  14. Historical: Liberation of Terra Volume 1, p. 104: "Rim Worlds Republic - [2767] Map"
  15. 15.0 15.1 Historical: Liberation of Terra Volume 1, p. 138: "Operation LIBERATION Wave 1 [July 2772 - December 2774]"
  16. First Succession War, pp. 24–25: "Inner Sphere - [2786] Map"
  17. First Succession War, p. 65: "The Best Defense is an Annoying Offense"
  18. Field Manual: Free Worlds League, p. 83: "Sirian Lancers: The Fury"
  19. Handbook: House Marik, p. 34: "Free Worlds League after First Succession War [2822]"
  20. First Succession War, pp. 112–113: "Inner Sphere - [2822] Map"
  21. Second Succession War, pp. 18–19: "Inner Sphere - 2830"
  22. Handbook: House Marik, p. 38: "Free Worlds League after Second Succession War [2864]"
  23. Second Succession War, pp. 78–79: "Inner Sphere - 2864"
  24. 24.0 24.1 House Marik (The Free Worlds League), p. 90: "Marik Militia"
  25. 25.0 25.1 25.2 25.3 25.4 Field Manual: Free Worlds League, p. 84
  26. 26.0 26.1 26.2 House Liao (The Capellan Confederation), p. 105: "Unit Deployment Table"
  27. 27.0 27.1 NAIS The Fourth Succession War Military Atlas Volume 2, pp. 16–17: "Tikonov Free Republic"
  28. NAIS The Fourth Succession War Military Atlas Volume 2, p. 16: "Tikonov Commonality (Map)"
  29. NAIS The Fourth Succession War Military Atlas Volume 2, p. 94: "End of the War"
  30. Historical: War of 3039, p. 133: "Inner Sphere - 3040"
  31. Era Report: 3052, p. 11: "Inner Sphere - 3050"
  32. Era Report: 3052, p. 23: "Inner Sphere - April 3052"
  33. Era Report: 3062, p. 29: "Inner Sphere - July 3063"
  34. 34.0 34.1 Field Manual: Updates, p. 159: "Free Worlds League Deployment Table"
  35. Handbook: House Liao, p. 68: "Capellan Confederation after FedCom Civil War - [3067] Map"
  36. Jihad: Final Reckoning, p. 43: "Inner Sphere - [3067] Map"
  37. Jihad: Final Reckoning, p. 62: "Inner Sphere Map - [March 3081]"
  38. Field Manual: 3085, p. vii: "Inner Sphere Map - [October 3085]"
  39. Era Report: 3145, p. 11: "Inner Sphere Map - [3135]"
  40. Inner Sphere - 3145
  41. Shattered Fortress, p. 103: "Inner Sphere - 3151" (Map)
  42. IlClan, p. 117: "One Step Closer to Glory"
  43. 43.0 43.1 43.2 43.3 The Price of Glory, ch. 1
  44. 44.0 44.1 44.2 The Price of Glory, pp. 5–10
  45. Gray Death Legion, 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
  46. The Price of Glory
  47. Dark Age: Republic of the Sphere, p. 22: "Prefecture IX"
  48. House Liao (The Capellan Confederation), p. 64
  49. The Price of Glory, p. 119
  50. 50.0 50.1 Chaos March, p. 91: "Sirian Holds"
  51. Dark Age: Republic Worlds (3130), p. 248: "Procyon"
  52. Jihad: Final Reckoning, p. 47: "The Jihad in Review"
  53. 53.0 53.1 First Succession War, p. 138: "First Succession War Deployment Table - FWLM"
  54. 54.0 54.1 House Liao (The Capellan Confederation), p. 106: "Unit Deployment Table"
  55. 55.0 55.1 ComStar, p. 84: "Com Guards Deployment Table"
  56. ComStar, p. 85
  57. Field Manual: Free Worlds League, p. 110: "Free Worlds League Deployment Table"
  58. Field Manual: Free Worlds League, p. 113: "Free Worlds League Deployment Table"
  59. Field Manual: Updates, p. 161: "Free Worlds League Deployment Table"
  60. Field Manual: Updates, p. 160: "Free Worlds League Deployment Table"
  61. Field Report: Clans, p. 15: "Clan Jade Falcon Deployment Status"
  62. Field Manual: 3145, p. 145: "Republic Armed Forces - Triarii Protectors"
  63. First Succession War, p. 125: "Shipbuilding Casualties of the First Succession War"
  64. The Star League, p. 164: "Top Ten Hegemony Companies - [Holden Planetary Engineers]"
  65. The Star League, p. 163: "Top Ten Hegemony Companies - [Mitchell Vehicles Interstellar]"
  66. Experimental Technical Readout: Primitives, Volume 5, p. 10: "Asher Hover Scout"