What the catalog contributes to generating one cell.
The magnitude envelope and sparse counts are derived from the catalog before crossing into a worker. Legacy addresses also retain their original cell count.
universe/src/galaxy.ts:208Members
catalogedreadonly
Cataloged stars already in this cell, for legacy P-address generation.
completeRadiusreadonly
Distance from the Sun inside which the catalog is complete for the kind of star this generator makes, and procedural fill is therefore suppressed.
Without it the fill happily invents an M dwarf 3.4 light-years away — closer than Proxima Centauri, and a discovery that would have made the news. The density model is right about how many stars there are and wrong about how many are unknown, and near the Sun that difference is the whole quantity.
The cost, stated: the volume inside this radius ends up slightly under-populated. RECONS counts 462 objects within 10 parsecs where HYG has 324, and the ~140 missing are brown dwarfs and close companions — real objects this now declines to invent. Under-populating with things that would be L and T dwarfs is a smaller lie than over-populating with things that would be front-page news.
magnitudeCoveragereadonly
The catalog's magnitude coverage, carried explicitly across a worker boundary.