We present 12 new transit observations of the exoplanet WASP-46b obtained with the 1.54-m telescope at Estación Astrofísica de Bosque Alegre ( EABA , Argentina ) and the 0.40-m Horacio Ghielmetti and 2.15-m Jorge Sahade telescopes at Complejo Astronómico El Leoncito ( CASLEO , Argentina ) .
We analyse them together with 37 light curves from the literature to re-determine the physical parameters and search for additional planets via transit timing variations ( TTVs ) .
We consider the 31 transits with uncertainties in their mid-transit times ( e _ { \mathrm { T _ { 0 } } } ) < 1 minute , to perform the first homogeneous study of TTVs for the system , finding a dispersion of \sigma = 1.66 minutes over a 6 year baseline .
Since no periodic variations are found , our interpretation for this relatively high value of \sigma is that the stellar activity could be affecting the measured mid-transit times .
This value of dispersion allows us to rule out the presence of additional bodies with masses larger than 2.3 , 4.6 , 7 , and 9.3 M _ { \mathrm { \earth } } at the first-order mean-motion resonances 2:1 , 3:2 , 4:3 , and 5:4 with the transiting planet , respectively .
Despite the 6 year baseline and a typical light curve precision of 2 \times 10 ^ { -3 } , we find that we can not significantly demonstrate a slow decrease of the orbital period of WASP-46b .
We place a lower limit of Q _ { \star } > 7 \times 10 ^ { 3 } on the tidal quality factor and determine that an additional 6 year baseline is required to rule out Q _ { \star } < 10 ^ { 5 } .