Analysis of Microlensing Light Curves Induced by Multiple-Planet Systems

To maximize the number of planet detections by increasing efficiency, current microlensing follow-up observation experiments are focusing on high-magnification events to search for planet-induced perturbations near the peak of lensing light curves. It was known that by monitoring high-magnification events, it is possible to detect multiplicity signatures of planetary systems. However, it was believed that the interpretation of the signals and the characterization of the detected multiple-planet systems would be difficult due to the complexity of the magnification pattern in the central region combined with the large number of lensing parameters required to model multiple-planet systems. In this paper, we demonstrate that in many cases the central planetary perturbations induced by multiple planets can be well approximated by the superposition of the single planetary perturbations where the individual planet-primary pairs act as independent binary lens systems (binary superposition). The validity of the binary-superposition approximation implies that the analysis of perturbations induced by multiple planets can be greatly simplified because the anomalies produced by the individual planet components can be investigated separately by using relatively much simpler single-planetary analysis, and thus enables better characterization of these systems.