Mysterious ripples moving through the disc of AU Microscopii

This short timelapse sequence shows images of the debris disc around the nearby star AU Microscopii in 2010, 2011 and 2014. The two earlier images were from the NASA/ESA Hubble Space Telescope and the final one from the new SPHERE instrument on ESO's Very Large Telescope. Ripple-like dust features in the disc are moving rapidly away from the star.