ALMA Reveals A Collision Between Protostellar Outflows in BHR71
  For a binary protostellar outflow system in which its members are located so
close to each other (the separation being smaller than the addition of the
widths of the flows) and with large opening angles, the collision seems
unavoidable regardless of the orientation of the outflows. This is in contrast
to the current observational evidence of just a few regions with indications of
colliding outflows. Here, using sensitive observations of the Atacama Large
Millimeter/Submillimeter Array (ALMA), we report resolved images of carbon
monoxide (CO) towards the binary flows associated with the BHR71 protostellar
system. These images reveal for the first time solid evidence that their flows
are partially colliding, increasing the brightness of the CO, the dispersion of
the velocities in the interaction zone, and changing part of the orientation in
one of the flows. Additionally, this impact opened the possibility of knowing
the 3D geometry of the system, revealing that one of its components (IRS2)
should be closer to us.
