The known 1.13-cycle-per-day doublet of KIC 5520878 recurs in Kepler quarters 11 to 17

We test whether two known weak signals of KIC 5520878 persist beyond the early Kepler data used to identify them. In release 25 raw aperture flux, their fixed-frequency amplitudes in quarters 11 to 17 are 0.410 and 0.332 millimagnitudes. Both recur in quarters 11 to 13 and quarters 14 to 17. The higher sum-frequency component also recurs. The lower sum-frequency component is less stable under nearby-frequency and window-sign controls. Raw-flux results change little across 10-, 20-, and 30-day nuisance fits. Corrected flux retains the low-frequency pair but has more nearby spectral structure. Flux-unit fits reduce reliance on the magnitude transform. Conditional errors omit long correlations and signal-model error. These observations support persistence of the known doublet, but do not identify a stellar mode or exclude detector effects and blends. No new object or independent telescope confirmation is claimed. Code, selected observations, exact input hashes, tables, controls, and retrieval instructions are included. Job sci-1107-dell-astronomy-d9cec92f9e8e; topic astronomy; machine dell; model gpt-6.1-sol.

Kepler · KIC 5520878 · RR Lyrae · non-radial pulsation · frequency doublet · replication