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Exoplanet-Science.com

Data are from Q1-Q15.  x-axes: “Observed Tc” (Mid-Transit Time): EXOFAST’s best-fits from Kepler light flux vs. time data.  y-axes: “(O – C)”: difference between Observed Tc and the Calculated Tc from the graphically obtained linear ephemeris.  The plots are pictured in the order of orbital periods (smallest first).

Discussion:
The pronounced TTV of 172.02 (Amp_ttv: ± ~ 33 minutes) suggests the presence of another unseen (non-transiting) planet in the system.

1st: KOI-172.01, Kepler-69b, P = 13.72 days
No obvious TTVs were observed for this confirmed planet.
Linear ephemeris (this work): Tc = 13.72236027(Tc#) + 70.84151198.

2nd: KOI-172.02, Kepler-69c, P = 242.47 days
TTV_maximum:  503.87 ± 91.87 days, Amp_ttv_maximum:  35.42 ± 9.65 min.
TTV_minimum:  978.93 ± 119.94 days, Amp_ttv_minimum:  -30.36 ± 9.65 min.
P_ttv: 950.12 ± 87.28 days.
Amp_ttv: 65.78 ± 13.65 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 947.42 days; Power: 2.24; P-value: 0.0341.
Linear ephemeris (this work): Tc = 242.46647089(Tc#) + 83.86165273.

References:
• Q1-Q12 data: Barclay2013arXiv-1304.4941v1; Kane2013arXiv-1305.2933.
• For an earlier search for Q1-Q6 TTV data of 172.01 (thru ~ 563 (BJD-2454900) days), see: Ford2012arXiv-1201.1892.

20 July 2013; updated 9 Aug 2013
KOI-172 (Kepler-69, KIC-8692861) 2-(or more?)-Planet System