This archive tracks four layers. A record present in 3 of them (AoI, M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
imperium
Capital of the Helican Subsector
The subsector's seat of government for most of its history, and a comfortable one — estates, hunting country and old money.
The 41st Millenniumpre-Rift
imperium
Fortress world; former subsector capital
Lost the capital to Thracian Primaris in 241.M41 and kept the aristocracy. An inquisitor of the Ordo Xenos kept a house here, which is how it ends up in the record at all; by the 13th Black Crusade it is a fortress world raising Neo-Cadian regiments.
Era Indomituspost-Rift
imperium
Frontline world
Sits in the Cadian Gate region with the Rift open beside it, and has been fighting a losing defensive war since.
Position
Map frame: 262, 322 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 297 units ≈ 31.6k light years, north-west of the galactic core.
Height above the disk plane: 3.8 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Gudrun System
Books set here
3 titles in the reading tracker touch this record, 1 of them as a primary location. Titles link out to the tracker.
wh40k.lexicanum.com/wiki/Gudrun infobox Class = War World, Civilised World, Fortress World; https://wh40k.lexicanum.com/wiki/Gudrun_System calls it a 'Fortress World, Neo-Cadian Recruiting World'
wh40k.lexicanum.com/wiki/Gudrun_System derived: — 'a System of Segmentum Obscurus in the Cadian Gate region'. The Scarus Sector is placed as a group immediately spinward of Cadia, which is the only published relationship between Scarus and any world already in this dataset. Gudrun anchors the group, being the world whose system carries the Cadian Gate statement