Scroll Down  to

KOI's (Blue)  or
K2 Objects (Green)

Exoplanet-Science.com

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:
There is an obvious sinusoidal TTV for the middle exoplanet candidate, 271.02, but not for the inner and outer ones (271.03 and 271.01). This suggests the presence of another unseen (non-transiting) exoplanet located somewhere between the orbits of 271.03 and 271.01.  Such close packing is reminiscent of other multi-planet systems, like part of the Kepler-11 system.

1st: KOI-271.03, P = 14.44 days [Plot error bars = ± 4.81 min.]
No observable sinusoidal character to TTVs.
Linear ephemeris (this work): Tc = 14.43594371(Tc#) + 74.50974546

2nd: KOI-271.02, P = 29.39 days [Plot error bars = ± 3.15 min.]
TTV_maximum: 217.84 ± 63.71 days, Amp_ttv_maximum: 8.69 ± 2.52 min.
TTV_minimum: 667.22 ± 77.57 days, Amp_ttv_minimum: -11.69 ± 2.52 min.
TTV_maximum: 1116.61 ± 99.82 days, Amp_ttv_maximum: 8.69 ± 2.52 min.
P_ttv: 898.76 ± 63.06 days.
Amp_ttv: 20.38 ± 3.56 minutes.
Lomb-Scargle periodogram, candidate P_ttv: 879.72 days; Power: 7.94; P-value: 0.00120.
Linear ephemeris (this work): Tc = 29.39316898(Tc#) + 142.06959525

3rd: KOI-271.01, P = 48.63 days [Plot error bars = ± 3.42 min.]
No observable sinusoidal character to TTVs.
Linear ephemeris (this work): Tc = 48.63034579(Tc#) + 105.54899034

Reference:
• For Q1-Q6 TTV data of 271.01 and 271.02 (thru ~ 563 (BJD-2454900) days), see: Ford2012arXiv-1201.1892.

20 Oct 2013
KOI-271 (Kepler-127, KIC-9451706) 4-(or more?)-Planet System