Properties of microlensing light curve anomalies induced by multiple planets

In this paper, we show that the pattern of microlensing light curve anomalies induced by multiple planets is well described by the superposition of those of the single-planet systems where the individual planet–primary binary pairs act as independent lens systems. As the outer deviation regions around the planetary caustics of the individual planets occur in general at different locations, we find that the pattern of anomalies in these regions is barely affected by the existence of other planet(s). This implies that even if an event is caused by a multiple planetary system, a simple single-planet lensing model is good enough for the description of most anomalies caused by the passage of the source through the outer deviation regions. Detection of the anomalies resulting from the source trajectory passing both the outer deviation regions caused by more than two planets will provide a new channel for detecting multiple planets.