TTVs are derived from Q1-Q16 Kepler data. 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.
P_520.03/P_520.01 = 2.018 ratio, near MMR of 2/1.The gravitational interaction between KOI-520.01 and 520.03 (and simultaneous support for their presence in the same star system) is evidenced by the excellent anti-correlation observed (above) for their sinusoidal TTV curves. In addition, reasonable agreement is found for their P_ttv's from their sinusoidal curves, their Lomb-Scargle periodograms, and from the estimate obtained with the Fabrycky equation (ref. below).
1st Plot: KOI-520.02, P = 5.43 days [Plot error bars = ± 8.77 min.]
Linear ephemeris (this work): Tc = 5.43310770(Tc#) + 71.36904024
2nd Plot: KOI-520.01, P = 12.76 days [Plot error bars = ± 5.12 min.]
TTV_minimum: 17.46 ± 98.28 days, Amp_ttv_minimum: -24.05 ± 4.16 min. (from curve, slightly outside data points).