On the Detection of Habitable Trojan Planets in the Kepler Circumbinary Systems

TL;DR

This study explores the potential for detecting habitable Trojan planets in Kepler circumbinary systems by analyzing orbital stability and transit timing variations, suggesting Kepler data could reveal such planets.

Contribution

The paper provides the first detailed analysis of the stability and detectability of habitable Trojan planets in Kepler circumbinary systems using N-body simulations and transit timing variation calculations.

Findings

Stable Trojans are confined to narrow orbital ranges.

Transit timing variations are within Kepler's detection capabilities.

Kepler data can potentially identify habitable Trojan planets.

Abstract

We present the results of a study of the prospect of detecting habitable Trojan planets in the Kepler Habitable Zone circumbinary planetary systems (Kepler-16, -47, -453, -1647, -1661). We integrated the orbits of 10,000 separate N-body systems (N=4,6), each with a one Earth-mass body in a randomly selected orbit near the L4 and L5 Lagrangian points of the host HZ circumbinary planet. We find that stable Trojan planets are restricted to a narrow range of semimajor axes in all five systems and limited to small eccentricities in Kepler-16, -47, and -1661. To assess the prospect of the detection of these habitable Trojan planets, we calculated the amplitudes of the variations they cause in the transit timing of their host bodies. Results show that the mean amplitudes of the transit timing variations (TTVs) correlate with the mass of the transiting planet and range from 70 minutes for Kepler-16b to 390 minutes for Kepler-47c. Our analysis indicates that the TTVs of the circumbinary planets caused by these Trojan bodies fall within the detectable range of timing precision obtained from the Kepler telescope's long-cadence data. The latter points to Kepler data as a viable source to search for habitable Trojan planets.