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.

Figure: KOI-1353.01, P = 125.87 days [Plot avg. error bars = ± 1.38 min.]
TTV_minimum: 428.71 ± 55.37 days, Amp_ttv_minimum: -5.70 ± 1.48 min.
TTV_maximum: 952.15 ± 74.74 days, Amp_ttv_maximum: 8.96 ± 1.48 min.
P_ttv: 1046.88 ± 61.82 days.
Amp_ttv: 14.66 ± 2.09 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 1047.11 days; Power: 3.47; FAP: 0.0397.
Linear ephemeris (this work): Tc = [125.86526608 ± 0.00038406](Tc#) + [169.66185382 ± 0.00222624]


Numerous literature and major Tc#, Tc, and TTV tabulation references can be found on my "Summary" webpage following the table.

28 May 2015
      Kepler KOI-1353 (Kepler-289; KIC-7303287) 3-(or more?)-Planet System

Discussion:
A sinusoidal curve-fit of the [(O-C) vs. Time] data for KOI-1353.01 (Kepler-289c) showed (Figure below) a periodicity (P_ttv) of 1046.88 ± 61.82 days; a Lomb-Scargle Periodogram (LSP) of the same data gave a medium-credibility periodicity of 1047.11 days.  Potentially, one other non-transiting planet is gravitationally interacting with KOI-xxx in this stellar system.

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