Five new transit light curves of TrES-3

Together with other light-curve data from the literature, 23 transit light curves in total, which cover an overall timescale of 911 epochs, have been analyzed through a standard procedure. From these observational data, the system's orbital parameters are determined and possible transit timing variations (TTVs) are investigated.

Given that a null TTV produces a fit with reduced {chi}^2^=1.52, our results agree with previous work, that TTVs might not exist in these data. However, a one-frequency oscillating TTV model, giving a fit with a reduced {chi}^2^=0.93, does possess a statistically higher probability. It is thus concluded that future observations and dynamical simulations for this planetary system will be very important.