Abstract:
We present 12 new transit light curves of the hot-Jupiter TrES-3b observed during 2012−2018 to probe the transit
timing variation (TTV). By combining the midtransit times determined from these 12 transit data with those
reestimated through uniform procedure from 71 transit data available in the literature, we derive new linear
ephemeris and obtain the timing residuals that suggest the possibility of TTV in the TrES-3 system. However, the
frequency analysis shows that the possible TTV is unlikely to be periodic, indicating the absence of an additional
body in this system. To explore the other possible origins of TTV, the orbital decay and apsidal precession
ephemeris models are fitted to the transit time data. We find the decay rate of TrES-3b to be P˙
q =- 4.1 3.1 ms
yr−1
, and the corresponding estimated modified stellar tidal quality factor of Q ¢ ~ ´ 1.11 105
* is consistent with
the theoretically predicted values for the stars hosting the hot-Jupiters. The shift in the transit arrival time of TrES3b after 11 years is expected to be Tshift ∼ 69.55 s, which is consistent with the rms of the timing residuals.
Besides, we find that the apsidal precession ephemeris model is statistically less probable than the other considered
ephemeris models. It is also discussed that despite the fact that the linear ephemeris model appears to be the most
plausible model to represent the transit time data, the possibility of the orbital decay cannot be completely ruled out
in the TrES-3 system. To confirm this, further high-precision and high-cadence follow-up observation of transits of
TrES-3b would be important.
