(References to Castor)
Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
X: -40.40 Y: -16.80 [e]
Although no exact stellar data is known for the Castor system, transit from the nadir jump point to the planet is an eight days journey at 1g acceleration and the system has (at least) six planets. Castor VI, which may or may not be inhabited, has several moons, with a pirate jump point existing just beyond the most distant moon.
 Planetary Garrison
 Owner History
- 2596 - Terran Hegemony 
- 2750 - Terran Hegemony 
- 2765 - Terran Hegemony 
- 3025 - Free Worlds League 
- 3079 - Free Worlds League 
- 3130 - Republic of the Sphere 
- 3135 - Independent world 
- 3145 - Wolf Empire 
 Planetary History
 Reunification War
 Amaris Civil War
The Castor system became the resting place of the SLS Nelson, a Black Lion-class battlecruiser and winner of the Star League Defense Force Martial Olympiad in 2732; the Nelson played an important part in the liberation of Oliver, but took heavy damage in the process. The crew of the Nelson managed to nurse her as far as the SLDF fleet station in the Castor system, only for the SLDF command to declare that the Nelson wasn't considered a viable candidate for repair. As a result of this decision the Nelson was scuttled and abandoned in a long elliptical orbit around Castor.
 Clan Invasion Era
With the assistance of the Word of Blake the Free Worlds League discovered the location of the Nelson in the Castor system and retrieved her, transporting her to the Ionus system to be repaired in secret at the Illium Shipyards before returning her to active service under a new designation, that of the FWLS Xanthos.
 The Jihad
On the 23rd of September 3075 Castor was one of three worlds in the Protectorate to be raided simultaneously by unidentified forces. The raiders damaged the defending Protectorate and Militia forces, and were rumoured to actually be drawn from the Word of Blake's own Shadow Divisions.
 Nearby Planets
- ↑ The Kell Hounds, p. 5
- ↑ ComStar (sourcebook), p. 85, "Com Guards Deployment Table"
- ↑ Field Report: FWLM, p. 14, "Regimental Status"
- ↑ 4.0 4.1 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"
- ↑ Field Report: FWLM, p. 17, "FWLM Deployment Map "
- ↑ Map of the Inner Sphere 3130
- ↑ Era Report: 3145, p. 10, "Inner Sphere - 3135"
- ↑ Era Report: 3145, p. 39, "Inner Sphere - 3145"
- ↑ 11.0 11.1 Field Manual: Free Worlds League, p. 119, "Renovation/Construction"
- ↑ Jihad Hot Spots: Terra, p. 18, "Timeline of the Jihad"
- ↑ Jihad: Final Reckoning, p. 54, "The Jihad In Review"