A search for transit timing variations and orbital decay in WASP-46b

PETRUCCI, R.; JOFRÉ, E.; FERRERO, L. V.; CÚNEO, V.; SAKER, L.; LOVOS, F.; GÓMEZ, M.; MAUAS, P.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 vol. 473 p. 5126 - 5141

0035-8711

We present 12 new transit observations of the exoplanet WASP-46bobtained with the 1.54-m telescope at Estación Astrofísicade Bosque Alegre (EABA, Argentina) and the 0.40-m Horacio Ghielmetti and2.15-m Jorge Sahade telescopes at Complejo Astronómico ElLeoncito (CASLEO, Argentina). We analyse them together with 37 lightcurves from the literature to re-determine the physical parameters andsearch for additional planets via transit timing variations (TTVs). Weconsider the 31 transits with uncertainties in their mid-transit times(e_T0) < 1 min, to perform the first homogeneous study ofTTVs for the system, finding a dispersion of σ = 1.66 min over a 6yr baseline. Since no periodic variations are found, our interpretationfor this relatively high value of σ is that the stellar activitycould be affecting the measured mid-transit times. This value ofdispersion allows us to rule out the presence of additional bodies withmasses larger than 2.3, 4.6, 7 and 9.3 M_{oplus} at the first-ordermean-motion resonances 2:1, 3:2, 4:3 and 5:4 with the transiting planet,respectively. Despite the 6 yr baseline and a typical light-curveprecision of 2 × 10-3, we find that we cannotsignificantly demonstrate a slow decrease of the orbital period ofWASP-46b. We place a lower limit of Q⋆ > 7 ×103 on the tidal quality factor and determine that anadditional 6 yr baseline is required to rule out Q⋆ <105.