canonicalSystemId

The canonical id for a system, from its primary component's designations.

Order, most stable first:

1. SOL — the one hard-coded identity, because the Sun has no catalog number in any of these and every other rule would give it an id that changes when the source does.
2. HIP… — Hipparcos. Assigned once in 1997, never reissued, and the widest coverage of the four (78% within 150 ly).
3. GJ… — Gliese. Stable, and the fallback that covers most of what Hipparcos missed, because the nearby-star catalog is exactly where the faint red dwarfs are.
4. HD…, then HR… — older and brighter-biased, so they only ever catch stars the first three missed.
5. The source row key, as HYG…. Reported by the ingest as a count, because these are the ids that a catalog rebuild can change, and a change here is a save file pointing at nothing.

sourceIdentitySource

Undocumented