Kepler KOI-1078 (Kepler-267; KIC-10166274) 4-(or more?)-Planet System
Discussion: A sinusoidal curve-fit of the [(O-C) vs. Time] data for KOI-1078.03 (Kepler-267d) showed (Figure below) a periodicity (P_ttv) of 332.78 ± 8.52 days; a Lomb-Scargle Periodogram (LSP) of the same data gave a low-credibility periodicity of 334.39 days. Potentially, a 4th non-transiting planet is gravitationally interacting with KOI-1078.03 in this stellar system.
TTVs are derived from Q1-Q17 Kepler data. x-axes: “Observed Tc” (Mid-Transit Time): EXOFAST’s best-fits from Normalized PDCSAP_FLUX Kepler light flux vs. time (BJD_tdb - 2454900) data. y-axes: “(O – C)”: difference between Observed Tc and the Calculated Tc from the graphically obtained linear ephemeris.