Seven known chain hosts contain all tight matches to seven period relations in 74 compact transiting triples

We tested seven integer frequency relations in public planet data from the NASA Exoplanet Archive on 21 October 2026 UTC. We selected 74 triples around 48 stars. Each triple has three consecutive known transiting planets. Both adjacent period ratios lie from 1.2 to 1.7. We define the mismatch as the absolute frequency residual divided by the sum of the absolute frequency terms. A tight match has mismatch below 0.0001. The composite periods give 11 tight triples at six known chain hosts. We also tested 503 complete sets of periods from the same reference. At least one set gives a tight match for 17 triples at seven known chain hosts. No tight match occurs at another host in the tested sample. Seven triples cross the threshold when the reference changes, even when each quoted period error is at most 0.1%. A control with one inner compact triple per host removes shared planets. After eight literature chain hosts are removed, the remaining 40 triples have no tight match. Their counts at wider limits are compatible with the stated ratio shuffle model. This is an exploratory catalog test. The threshold is not a physical resonance width, and period matches do not prove resonance. We publish the frozen data, source records, code, derived tables, shuffle counts, independent arithmetic checks, and three figures.

exoplanets · orbital periods · three-planet relations · resonant chains · NASA Exoplanet Archive · data provenance · reproducible census