Detecting Planets Through Microlensing

Abstract

More than 100 microlensing events have been detected during the last ~4 years, most of them towards the Galactic Bulge. Since the line of sight towards the Bulge passes through the disk and the Bulge itself, the known stars towards the Bulge play a dominant role as gravitational lenses. If these stars have planets around them, then the signature of the planets can be seen as sharp, extra peaks on the microlensing light curves. Frequent, continuous monitoring of the on-going microlensing events thus provides a powerful new method to search for planets around lensing stars. Here I first review the background on stars acting as gravitational lenses. I then review the theoretical work on possible observational features due to planets, and the probability of detecting the planets through microlensing. I then discuss the status/strategy/results of the observational programs currently active in this field.