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-4076.01, P = 124.83 days [Plot avg. error bars = ± 11.09 min.]
TTV_maximum: 242.60 ± 128.50 days, Amp_ttv_maximum: 35.62 ± 19.32 min.
TTV_minimum: 619.60 ± 154.48 days, Amp_ttv_minimum: -38.10 ± 19.32 min.
TTV_maximum: 996.60 ± 194.02 days, Amp_ttv_maximum: 35.62 ± 19.32 min.
TTV_minimum: 1373.61 ± 240.52 days, Amp_ttv_minimum: -38.10 ± 19.32 min.
P_ttv: 754.01 ± 113.38 days.
Amp_ttv: 73.72 ± 27.32 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 751.70 days; Power: 2.24; FAP: 0.252.
Linear ephemeris (this work): Tc = [124.82934016 ± 0.00294325](Tc#) + [141.77292545 ± 0.01741252]


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

14 April 2015
                  Kepler KOI-4076 (KIC-9455677) 2-(or more?)-Planet System

Discussion:
In the example of KOI-4076.01, a sinusoidal curve-fit of the (O-C) vs. Time data showed (Figure below) a periodicity (P_ttv) of 754.01 ± 113.38 days; 751.70 days was observed in the Lomb-Scargle Periodogram (LSP) of the same data.

Exoplanet-Science.com

Scroll Down  to

KOI's (Blue)  or
K2 Objects (Green)