Abstract
| - The exoplanet KOI-142b (Kepler-88b) shows transit timing variations (TTVs) with a semi-amplitude of ~12 h, which earned it the nickname “king of transit variations”. Only the transit of planet b was detected in the Kepler data with an orbital period of ~10.92 days and a radius of ~0.36 RJup. The TTVs together with the transit duration variations of KOI-142b were analysed recently, finding a unique solution for a companion-perturbing planet. An outer non-transiting companion was predicted, KOI-142c, with a mass of 0.626 ± 0.03 MJup and a period of 22.3397 -0.0018+0.0021 days, which is close to the 2:1 mean-motion resonance with the inner transiting planet. We report an independent confirmation of KOI-142c using radial velocity observations with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We derive an orbital period of 22.10 ± 0.25 days and a minimum planetary mass of 0.76 0.16+0.32MJup, both in good agreement with the predictions by previous transit timing analysis. Therefore, this is the first radial velocity confirmation of a non-transiting planet discovered with TTVs, providing an independent validation of the TTVs technique.
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