GW Ori: Interactions Between a Triple-star System and its Circumtriple
  Disk in Action
  GW Ori is a hierarchical triple system which has a rare circumtriple disk. We
present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3
mm dust continuum and 12CO J=2-1 molecular gas emission of the disk. For the
first time, we identify three dust rings in the disk at ~46, 188, and 338 AU,
with estimated dust mass of ~70-250 Earth masses, respectively. To our
knowledge, the outer ring in GW Ori is the largest dust ring ever found in
protoplanetary disks. We use visibility modelling of dust continuum to show
that the disk has misaligned parts and the innermost dust ring is eccentric.
The disk misalignment is also suggested by the CO kinematics modelling. We
interpret these substructures as evidence of ongoing dynamical interactions
between the triple stars and the circumtriple disk.
