Exoplanetary Microlensing

Understand

Gravitational microlensing occurs when a foreground star happens to pass very close to our line of sight to a more distant background star.

• The foreground star acts as a lens, splitting the light from the source star into two images, which are typically unresolved.
• However, these images are also magnified, by an amount that depends on the angular lens-source separation.
• The relative lens-source motion results in a time-variable source magnification: a microlensing event.