The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion
  Protostars. III. Substructures in Protostellar Disks
  The prevalence of substructures in $\sim1-10$ Myr old protoplanetary disks,
which are often linked to planet formation, has raised the question of how
early such features form, and as a corollary, how early planet formation
begins. Here we present observations of seven protostellar disks (aged
$\sim0.1-1$ Myr) from the VLA/ALMA Nascent Disk and Multiplicity Survey of
Orion Protostars (VANDAM: Orion) that show clear substructures, thereby
demonstrating that these features can form early in the lifetimes of disks. We
use simple analytic models as well as detailed radiative transfer modeling to
characterize their structure. In particular we show that at least four of the
sources have relatively massive envelopes, indicating that they are
particularly young, likely the youngest disks with substructures known to-date.
Several of these disks also have emission from an inner disk that is offset
from the center of the ring structure. Given the size of the cleared out
regions of the disk, it is unclear, however, whether these features are related
to planet formation, or rather if they are signposts of close-separation binary
formation at early times.
