Kepler KOI-4087 (Kepler-440b, KIC-6106282) 2-(or more?)-Planet System
TTV Evidence: There appears to be a pronounced TTV in the case of KOI-4087.01 (see plot) but the values for P_ttv and Amp_ttv are not well constrained (and are very different for the two analytical approaches (Lomb-Scargle Periodogram and sinusoidal curve-fit). This is very likely due to the considerably-less-than-one-cycle that was observed during the entire Q1-Q17 time frame.
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.