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TTVs are derived from Q0-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-4235.01, P = 66.64 days [Plot avg. error bars = ± 10.06 min.]
TTV_maximum: 117.31 ± 85.68 days, Amp_ttv_maximum: 14.99 ± 5.47 min.
TTV_minimum: 485.95 ± 96.38 days, Amp_ttv_minimum: -12.57 ± 5.47 min.
TTV_maximum: 854.59 ± 116.71 days, Amp_ttv_maximum: 14.99 ± 5.47 min.
TTV_minimum: 1223.23 ± 142.59 days, Amp_ttv_minimum: -12.57 ± 5.47 min.
P_ttv: 737.28 ± 69.02 days.
Amp_ttv: 27.55 ± 7.73 minutes.
Lomb-Scargle periodogram, periodicity (P_ttv): 734.74 days; Power: 3.56; FAP: 0.154 (borderline credibility).
Linear ephemeris (this work): Tc = 66.64318493(Tc#) + 103.08721502


Related TTV Tabulations and References:
• For Q0-6 TTV data (thru ~ 563 (BJD-2454900) days): Ford et al., 2012, arXiv-1201.1892.
• For Q0-10 TTV data (thru ~ 934 (BJD-2454900) days): Rowe et al., 2014, arXiv-1402.6534.
• For Q0-12 TTV data (thru ~ 1116 (BJD-2454900) days): Mazeh et al., 2013, arXiv-1301.5499.
• For Q0-12 Calc. properties from TTVs: Hadden & Lithwick, 2013, arXiv-1310.7942.
• For Q0-13/14 TTV data, Xie: http://www.astro.utoronto.ca/~jwxie/TTV/TTV_Home.html
• Two ground-based Kepler-TTV-follow-up programs are in place at the moment:
 --- Gary, "KAFO" project: http://brucegary.net/kafo/
 --- von Essen, "KOINet": http://koinet.astro.physik.uni-goettingen.de/

28 Apr 2014
            Kepler KOI-4235.01 (KIC-10794974) 2-(or more?)-Planet System

TTV Evidence:
The presence of both a credible (i.e.: False Alarm Probability (FAP) < 0.1) periodicity in the Lomb-Scargle Periodogram (LSP) of [(O-C) vs. Time] ("TTVxy") data points, along with a sinusoidal distribution of the same points displaying a closely corresponding periodicity ("P_ttv") (see Figure(s) below), is strongly suggestive of the presence of an unseen (non-transiting), gravitationally perturbing planetary object(s) in this system.