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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.

Discussion:
Shown on this page for the close-in (P = 3.34 days) Kepler-defined exoplanet candidate, KOI-139.02, consistent with a Lomb-Scargle periodicity from the same data of 46.45 days, is the best-fit sinusoidal curve teased from its [(O-C) vs. Tc] data that shows a repeating frequency ("P_ttv") of 46.46 ± 0.16 days.  The underlying cause of these observations is not known but it is reminiscent of the same effect disclosed for 774.01 and 676.02 (see corresponding pages).  Also shown is the TTV for the further-out exoplanet candidate, KOI-139.01, whose period (224.80 days) is the same as that of Venus (225 days) and may be within the habitable zone of the KOI-139 star.  The pronounced TTV suggests the presence of another unseen planetary object.  Indeed, given the architecture of the (now) large number of known multi-planet Kepler candidate and confirmed systems, it would not be surprising to find other planets with periods in between these 3.34-day and 224.80-day known ones.  The TTV for 139.01 was also noted in ~ 2012 by several "Planet Hunters", namely Troy Winaski (through his clever approach to uncovering TTVs; see: http://www.extrasolar.us), Kian Jek, Johann Sejpka, and "planetsam" (see:  http://talk.planethunters.org/discussions/DPH101e8tx?object_id=APH10277516).

1st: KOI-139.02, P = 3.34 days [Plot error bars = ± 6.22 min.]
TTV_minimum: 65.65 ± 2.95 days, Amp_ttv_minimum: -13.98 ± 3.25 min.
TTV_maximum: 88.89 ± 2.95 days, Amp_ttv_maximum: 13.69 ± 3.25 min.
TTV_minimum: 112.12 ± 2.96 days, Amp_ttv_minimum: -13.98 ± 3.25 min.
TTV_maximum: 135.35 ± 2.97 days, Amp_ttv_maximum: 13.69 ± 3.25 min.
(+ 54 other intervening minima & maxima)
TTV_minimum: 1413.06 ± 5.61 days, Amp_ttv_minimum: -13.98 ± 3.25 min.
TTV_maximum: 1436.29 ± 5.68 days, Amp_ttv_maximum: 13.69 ± 3.25 min.
TTV_minimum: 1459.53 ± 5.75 days, Amp_ttv_minimum: -13.98 ± 3.25 min.
TTV_maximum: 1482.76 ± 5.82 days, Amp_ttv_maximum: 13.69 ± 3.25 min.
P_ttv: 46.46 ± 0.16 days.
Amp_ttv: 27.67 ± 4.60 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 46.45 days; Power: 12.70; P-value: 0.0112.
Linear ephemeris (this work): Tc = 3.34179440(Tc#) + 74.35766990

2nd: KOI-139.01, P = 224.80 days [Plot error bars = ± 1.44 min. (within plot symbols)]
TTV_maximum: 468.85 ± 131.28 days, Amp_ttv_maximum: 57.27 ± 26.38 min.
TTV_minimum: 1026.40 ± 177.15 days, Amp_ttv_minimum: -57.54 ± 26.38 min.
P_ttv: 1115.10 ± 145.26 days.
Amp_ttv: 114.81 ± 37.30 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 1121.22 days; Power: 2.13; P-value: 0.160.
Linear ephemeris (this work): Tc = 224.77917829(Tc#) + 75.10258586

References:
• For Q0-Q6 TTV data of 139.01 (thru ~ 563 (BJD-2454900) days), see: Ford et al., 2012, arXiv-1201.1892.
• For Q0-12 TTV data of 139.01 and 139.02 (thru ~ 1116 (BJD-2454900) days), see: Mazeh et al., 2013, arXiv-1301.5499.

11 Nov 2013
KOI-139 (Kepler-111, KIC-8559644) 3-(or more?)-Planet System