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

BALUEV, R.V.; SOKOV, E.N.; JONES, H.R.A.; SHAIDULIN, V.S.; SOKOVA, I.A.; NIELSEN, L.D.; BENNI, P.; SCHNEITER, E.M.; VILLARREAL D'ANGELO, C.; FERNÁNDEZ-LAJÚS, E.; DI SISTO, R.P.; BA?TÜRK, Ö.; BRETTON, M.; WUNSCHE, A.; HENTUNEN, V.-P.; SHADICK, S.; JONGEN, Y.; KANG, W.; KIM, T.; PAK?TIENE, E.; QVAM, J.K.T.; KNIGHT, C.R.; GUERRA, P.; MARCHINI, A.; SALVAGGIO, F.; PAPINI, R.; EVANS, P.; SALISBURY, M.; GARCIA, F.; MOLINA, D.; GARLITZ, J.; ESSEIVA, N.; OGMEN, Y.; KARAVAEV, Y.; RUSOV, S.; IBRAHIMOV, M.A.; KARIMOV, R.G.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 490 p. 1294 - 1312

0035-8711

We homogeneously analyse ∼3.2 × 105 photometric measurements for ∼1100 transit light curves belonging to 17 exoplanet hosts. The photometric data cover 16 years (2004–2019) and include amateur and professional observations. Old archival light curves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening models. We also derive self-consistent transit and radial-velocity fits for 13 targets. We confirm the nonlinear transit timing variation (TTV) trend in the WASP-12 data at a high significance, and with a consistent magnitude. However, Doppler data reveal hints of a radial acceleration of about −7.5 ± 2.2 m s−1 yr−1, indicating the presence of unseen distant companions, and suggesting that roughly 10 per cent of the observed TTV was induced via the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected after the recent TESS observations appears controversial and model dependent. It is not supported by our homogeneous TTV sample, including 10 ground-based EXPANSION light curves obtained in 2018 simultaneously with TESS. Even if the TTV trend itself does exist in WASP-4, its magnitude and tidal nature are uncertain. Doppler data cannot entirely rule out the Roemer effect induced by possible distant companions.