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-12.01, P = 17.86 days [Plot avg. error bars = ± 0.65 min.]
TTV_maximum: 73.04 ± 92.80 days, Amp_ttv_maximum: 1.01 ± 0.30 min.
TTV_minimum: 669.84 ± 116.44 days, Amp_ttv_minimum: -1.25 ± 0.30 min.
TTV_maximum: 1266.64 ± 162.64 days, Amp_ttv_maximum: 1.01 ± 0.30 min.
P_ttv: 1193.59 ± 126.08 days.
Amp_ttv: 2.26 ± 0.42 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 1207.41 days; Power: 8.88; FAP: 0.0988.
Linear ephemeris (this work): Tc = [17.85522460 ± 0.00000557](Tc#) + [79.59736448 ± 0.00025152]


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

30 Jun 2015

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    Kepler KOI-12.01 (Kepler-448b; KIC-5812701) 2-(or more?)-Planet System

Discussion:
A sinusoidal curve-fit of the [(O-C) vs. Time] data for KOI-12.01 showed (Figure below) a periodicity (P_ttv) of 1193.59 ± 126.08 days; a Lomb-Scargle Periodogram (LSP) of the same data gave a medium-credibility periodicity of 1207.41 days.  Potentially, one other non-transiting planet is gravitationally interacting with KOI-12.01 in this stellar system.