Microlensing of strongly interacting binary systems
  Many binary systems are in a state of strong interaction, where mass exchanges, accretion disks, common envelopes provide circumstellar matter which can have significant effects in microlensing light curves of background sources. Such chromatic absorption effects provide very interesting information on the nature of this diffuse matter and the physics of the interaction between the two stars. 
V. Bozza, L. Mancini