Morphological Complexity of Protostellar Envelopes
  Extinction maps at 8 micron from the Spitzer Space Telescope show that many
Class 0 protostars exhibit complex, irregular, and on-axisymmetric structure
within the densest regions of their dusty envelopes. Many of the systems have
highly irregular and on-axisymmetric morphologies on scales $\sim$1000 AU, with
a quarter of the sample exhibiting filamentary or flattened dense structures.
Complex envelope structure is observed in regions spatially distinct from
outflow cavities, and the densest structures often show no systematic alignment
perpendicular to the cavities. We suggest that the observed envelope complexity
is the result of collapse from protostellar cores with initially
non-equilibrium structures. The striking non-axisymmetry in many envelopes
could provide favorable conditions for the formation of binary systems. We then
show that the kinematics around L1165 as probed with N2H+ are indicative of
asymmetric infall; the velocity gradient is not perpendicular to the outflow.
