Gravitational lensing
In cases of microlensing, there is no distortion in shape. However, the amount of light visible from an object changes periodically. This can be used to detect exoplanets. Light from a distant star is bent and enhanced by the gravitational field of a closer star. The presence of an exo-planet rotating around that closer star bends the light of the star farther away periodically. Object OGLE-2005-BLG-390-Lb, discovered 25 January 2006, is the first exoplanet detected by using microlensing.