Substructure in the Circumstellar Disk Around the Young Star AU Microscopii
Michael C. Liu
Keck adaptive optics imaging with a physical resolution of 0.4
astronomical units (AU) resolves the inner (15 to 80 AU) disk
of AU Microscopii (AU Mic, GJ 803, HD 197481), the nearest known
scattered light disk to Earth. The inner disk is asymmetric
and possesses a sharp change in structure at 35 AU. The disk
also shows spatially localized enhancements and deficits at
25- to 40-AU separations. The overall morphology points to the
influence of unseen larger bodies and resembles structures expected
from recent planet formation. AU Mic is coeval with the archetypical
debris disk system ß Pictoris, and the similarities
between their two disks point to synchronous disk evolution.
Multiple indications of substructure appear to be common in
circumstellar disks at an age of

12 million years.
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA.
E-mail: mliu{at}ifa.hawaii.edu