Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 2K039
CHARACTERIZATION OF KOI-94 SYSTEM WITH PHOTOMETRIC LIGHT CURVES AND TRANSIT TIMING VARIATION ANALYSIS: IMPLICATION FOR THE PLANET-PLANET ECLIPSE
Masuda, Kento (The University of Tokyo)
Hirano, Teruyuki (Tokyo Institute of Technology)
Taruya, Atsushi (The University of Tokyo)
Nagasawa , Makiko (Tokyo Institute of Technology)
Suto, Yasushi (The University of Tokyo)
Abstract:
We report the analysis of the transit timing variations (TTVs) in Kepler Object of
Interest (KOI) 94 system using direct numerical integrations. We analyzed the photometric
light curve of KOI-94 obtained by the Kepler spacecraft to extract the transit
times of KOI-94c, KOI-94d, and KOI-94e, and found that they are significantly deviated from the exact periodicity due to the mutual gravitational interaction among the
planets, as pointed out by Weiss and coworkers. We fit these variations with numerical
simulations and obtained the constraints on the masses, eccentricities, and longitudes
of periastrons of the three planets, independently of the radial velocity measurements.
Our analysis shows that the TTV favors the solution with small (< 0.1) eccentricities
for all the three planets and with a rather small mass of KOI-94d (md = 52 } 7M⊕),
in contrast to the radial velocity result, md = 106 } 11M⊕. We also present analytic modeling of a gplanet-planet eclipse (PPE),h a rare mutual event in which two planets partially overlap with each other on the stellar disk in their double transit phase. We modeled the brightening caused by the PPE analytically, and derived the formula to reconstruct the sky-plane mutual inclination of the two eclipsing planets from the observed height, central time, and duration of the brightening. Based on this model, the implication of the results of TTV analysis for the time of the next PPE is also discussed.
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