Homogeneously derived transit timings for 17 exoplanets and reassessed TTV trends for WASP-12 and WASP-4

BALUEV, R V; SHAIDULIN, V SH; BENNI, P; SOKOV, E N; SOKOVA, I A; SCHNEITER, E M; JONES, H R A; NIELSEN, L D; VILLARREAL D?ANGELO, C

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019 vol. 490 p. 1294 - 1312

0035-8711

We homogeneously analyse∼3.2×105photometric measurements for∼1100 tran-sit lightcurves belonging to 17 exoplanet hosts. The photometric data cover 16 years2004?2019 and include amateur and professional observations. Old archival lightcurveswere reprocessed using up-to-date exoplanetary parameters and empirically debiasedlimb-darkening models. We also derive self-consistent transit and radial-velocity fitsfor 13 targets. We confirm the nonlinear TTV trend in the WASP-12 data at a highsignificance, and with a consistent magnitude. However, Doppler data reveal hints of aradial acceleration about (−7.5±2.2) m/s/yr, indicating the presence of unseen distantcompanions, and suggesting that roughly 10 per cent of the observed TTV was inducedvia the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected af-ter the recent TESS observations appears controversial and model-dependent. It is notsupported by our homogeneus TTV sample, including 10 ground-based EXPANSIONlightcurves obtained in 2018 simultaneously with TESS. Even if the TTVtrend itselfdoes exist in WASP-4, its magnitude and tidal nature are uncertain.Doppler datacannot entirely rule out the Roemer effect induced by possible distant companions.