Multiple Transits during a Single Conjunction: Identifying Transiting Circumbinary Planetary Candidates from TESS

TL;DR

This paper introduces a technique to identify circumbinary planet candidates from TESS data by analyzing multiple transits during a single conjunction, enabling orbital period estimation with limited observation time.

Contribution

The study presents a novel photometric method to estimate the orbital periods of circumbinary planets from limited transits, facilitating large-scale candidate identification from TESS.

Findings

Technique accurately estimates orbital periods within 10-20% for low-eccentricity systems.

Application to Kepler planets validates the method's effectiveness.

Potential to detect hundreds of circumbinary planets with TESS data.

Abstract

We present results of a study on identifying circumbinary planet candidates that produce multiple transits during one conjunction with eclipsing binary systems. The occurrence of these transits enables us to estimate the candidates' orbital periods, which is crucial as the periods of the currently known transiting circumbinary planets are significantly longer than the typical observational baseline of TESS. Combined with the derived radii, it also provides valuable information needed for follow-up observations and subsequent confirmation of a large number of circumbinary planet candidates from TESS. Motivated by the discovery of the 1108-day circumbinary planet Kepler-1647, we show the application of this technique to four of Kepler's circumbinary planets that produce such transits. Our results indicate that in systems where the circumbinary planet is on a low-eccentricity orbit, the estimated planetary orbital period is within <10-20% of the true value. This estimate is derived from photometric observations spanning less than 5% of the planet's period, demonstrating the strong capability of the technique. Capitalizing on the current and future eclipsing binaries monitored by NASA's TESS mission, we estimate that hundreds of circumbinary planets candidates producing multiple transits during one conjunction will be detected in the TESS data. Such a large sample will enable statistical understanding of the population of planets orbiting binary stars and shed new light on their formation and evolution.