SOPHIE velocimetry of Kepler transit candidates: X KOI-142c: first radial velocity confirmation of a non-transiting exoplanet discovered by transit timing

Abstract

The exoplanet KOI-142b (Kepler-88b) shows transit timing variations (TTVs) with a semi-amplitude of $\sim 12$ hours, earning the nickname of "king of transit variations". Only the transit of the planet b was detected in the Kepler data with an orbital period of $\sim 10.92$ days and a radius of $\sim 0.36$ R${}_{\mathrm{Jup}}$. The TTVs together with the transit duration variations (TDVs) of KOI-142b were analysed by Nesvorny et al. (2013) who found a unique solution for a companion perturbing planet. The authors predicted an outer non-transiting companion, KOI-142c, with a mass of $0.626\pm 0.03$ M${}_{\mathrm{Jup}}$ and a period of $22.3397_{-0.0018}^{+0.0021}$days, and hence close to the 2:1 mean-motion resonance with the inner transiting planet. We report 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 $22.10\pm 0.25$days and a minimum planetary mass of $0.76_{0.16}^{+0.32}$ M${}_{\mathrm{Jup}}$, 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 transit timing variations, providing an independent validation of the TTVs technique.

4 pages, 3 figures, A&A Accepted

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• SOPHIE velocimetry of Kepler transit candidates VII. A false-positive rate of 35% for Kepler close-in giant exoplanet candidates
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• Hidden Planetary Friends: On the Stability Of 2-Planet Systems in the Presence of a Distant, Inclined Companion
• Ground-based transit observations of the HAT-P-18, HAT-P-19, HAT-P-27/WASP-40 and WASP-21 systems
• Indications for transit timing variations in the exo-Neptune HAT-P-26b
• The architecture and formation of the Kepler-30 planetary system
• Models of radial velocities and transit light curves
• How to Find a Planet from Transit Variations