KOI-142, the King of Transit Variations, is a Pair of Planets near the 2:1 Resonance

TL;DR

This paper analyzes KOI-142, a planetary system near the 2:1 resonance, revealing a non-transiting Jupiter-mass companion and a Neptune-sized planet through transit timing and duration variations, providing insights into planetary formation.

Contribution

It presents the first detailed analysis of KOI-142's transit variations, detecting a non-transiting giant planet and characterizing the system's near-resonant dynamics.

Findings

Detection of a non-transiting Jupiter-mass companion.

Identification of a Neptune-sized transiting planet.

System's period ratio is just wide of 2:1 resonance.

Abstract

The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, 12-hour TTV amplitude. Here we report a thorough analysis of KOI-142.01's transits. We discover periodic Transit Duration Variations (TDVs) of KOI-142.01 that are nearly in phase with the observed TTVs. We show that KOI-142.01's TTVs and TDVs uniquely detect a non-transiting companion with a mass 0.7 that of Jupiter (KOI-142c). KOI-142.01's mass inferred from the transit variations is consistent with the measured transit depth, suggesting a Neptune class planet (KOI-142b). The orbital period ratio P_c/P_b=2.03 indicates that the two planets are just wide of the 2:1 resonance. The present dynamics of this system, characterized here in detail, can be used to test various formation theories that have been proposed to explain the near-resonant pairs of exoplanets.