The Eroding Disk of the Young M Star AU Mic

AU Mic (M1V, d=9.79 pc GAIA consortium 2016; t=24±3 Myr Bell et al. 2014) hosts a nearby debris disk. A distinctive feature is the presence of a series of arc-like structures on one side of the star. Comparison of SPHERE data from 2014 with HST data from 2010/2011 revealed the features were moving outward at between 4 -10 km/s (Boccaletti et al. 2015), and that 3 were moving at greater than escape velocity. The outward motion continues. HST observations resumed in 2017 October and confirm the disk is now more diffuse, and the features are now well-resolved. For the first time we find a velocity component orthogonal to the outer disk in addition to the motion along the disk. These findings are compared with available models.