Planet Detection via Microlensing

TL;DR

Microlensing is a promising method for detecting distant exoplanets, especially those with orbital separations similar to Earth's, complementing other detection techniques and aiding in understanding planetary frequency in the Milky Way.

Contribution

This paper reviews the potential of microlensing for exoplanet detection and provides strategic recommendations for ESO to develop competitive detection capabilities.

Findings

Microlensing effectively detects planets several kiloparsecs away.

Detection probability is weakly dependent on planetary mass.

Microlensing complements other exoplanet detection methods.

Abstract

Microlensing is the most promising method to study the statistical frequency of extra-solar planets orbiting typical (random) stars in the Milky Way, even those several kiloparsecs from Earth. The lensing zone corresponds to orbital separations of a few times the Earth-Sun distance (AU) -- a good match to many planets in our own Solar System -- and the probability of detection is a rather weak function of planetary mass. Microlensing is thus a perfect complement to radial velocity and astrometric techniques that allow the detailed study of nearby planets with larger masses and smaller orbital separations. This report forms Appendix C of the Final Report of the European Southern Observatory (ESO) Working Group on the Detection of Extrasolar Planets, which contains recommendations to ESO for designing a competitive strategy in the field of extrasolar planets. The full report is available from ESO as document SPG-VLTI-97/002.