Practical suggestions on detecting exomoons in exoplanet transit light curves

TL;DR

This paper proposes a novel method for directly detecting exomoons in raw transit light curves by analyzing the scatter in folded light curves, potentially improving detection sensitivity.

Contribution

It introduces a new approach that analyzes scatter in folded light curves to directly identify exomoons, unlike previous methods relying on post-processing timing parameters.

Findings

Scatter analysis enhances exomoon detection prospects.

Averaging folded light curves reduces signal, but scatter analysis preserves it.

Method improves detection sensitivity in realistic observational data.

Abstract

The number of known transiting exoplanets is rapidly increasing, which has recently inspired significant interest as to whether they can host a detectable moon. Although there has been no such example where the presence of a satellite was proven, several methods have already been investigated for such a detection in the future. All these methods utilize post-processing of the measured light curves, and the presence of the moon is decided by the distribution of a timing parameter. Here we propose a method for the detection of the moon directly in the raw transit light curves. When the moon is in transit, it puts its own fingerprint on the intensity variation. In realistic cases, this distortion is too little to be detected in the individual light curves, and must be amplified. Averaging the folded light curve of several transits helps decrease the scatter, but it is not the best approach because it also reduces the signal. The relative position of the moon varies from transit to transit, the moon's wing will appear in different positions on different sides of the planet's transit. Here we show that a careful analysis of the scatter curve of the folded light curves enhances the chance of detecting the exomoons directly.