Expansion of the Planet Detection Channels in Next-Generation Microlensing Surveys

TL;DR

This paper classifies planetary lensing signals and estimates detection rates for new channels in upcoming high-cadence, wide-field microlensing surveys, predicting a substantial increase in detectable wide-separation and free-floating planets.

Contribution

It introduces a classification of planetary signals and quantifies the expected detection rates for new channels in future microlensing surveys.

Findings

New detection channels could identify 15-30% of all planets.

A significant fraction of free-floating planets may be detected.

Future surveys will greatly expand the range of detectable exoplanets.

Abstract

We classify various types of planetary lensing signals and the channels of detecting them. We estimate the relative frequencies of planet detections through the individual channels with special emphasis on the new channels to be additionally provided by future lensing experiments that will survey wide fields continuously at high cadence by using very large-format imaging cameras. From this investigation, we find that the fraction of wide-separation planets that would be discovered through the new channels of detecting planetary signals as independent and repeating events would be substantial. We estimate that the fraction of planets detectable through the new channels would comprise ~15 -- 30% of all planets depending on the models of the planetary separation distribution and mass ratios of planets. Considering that a significant fraction of planets might exist in the form of free-floating planets, the frequency of planets to be detected through the new channel would be even higher. With the expansion of the channels of detecting planet, future lensing surveys will greatly expand the range of planets to be probed.