Analysis of variations in transit time and transit duration in WASP-3. Evidence of secular perturbations reconsidered
We investigate the variations in the transit parameters of WASP-3 over a period of time spanning more than 3 yr. Most of the works published about this planetary system after its discovery concentrate on variations in transit time analysis, whereas long-term variations in transit duration (TDV) have not been explored yet. Apart from providing complementary information on the geometrical configuration of the system, the investigation of TDV can also provide indirect evidence of the presence of additional planets. We find evidence of long-term TDV with an amplitude of 4-5 min. The analysis of periodicity suggests that a modulation may be present but we could not identify a clearly dominant period. We caution that due to the small size of the sample and the effects of the sampling window, additional observations are required to be able to determine true periods.