Proper motions of collimated jets from intermediate-mass protostars in
  the Carina Nebula
  We present proper motion measurements of 37 jets and HH objects in the Carina
Nebula measured in two epochs of H$\alpha$ images obtained $\sim 10$ yrs apart
with HST/ACS. Transverse velocities in all but one jet are faster than $\gtrsim
25$ km s$^{-1}$, confirming that the jet-like H$\alpha$ features identified by
Smith et al. (2010) trace outflowing gas. Proper motions constrain the location
of the jet-driving source and provide kinematic confirmation of the
intermediate-mass protostars that we identify for 20/37 jets. Jet velocities do
not correlate with the estimated protostar mass and embedded driving sources do
not have slower jets. Instead, transverse velocities (median $\sim 75$ km
s$^{-1}$) are similar to those in jets from low-mass stars. Assuming a constant
velocity since launch, we compute jet dynamical ages (median $\sim 10^4$ yr).
If continuous emission from inner jets traces the duration of the most recent
accretion bursts, then these episodes are sustained longer (median $\sim 700$
yr) than the typical decay time of an FU Orionis outburst. These jets can carry
appreciable momentum that may be injected into the surrounding environment. The
resulting outflow force, $dP/dt$, lies between that measured in low- and
high-mass sources, despite the very different observational tracers used.
Smooth scaling of the outflow force argues for a common physical process
underlying outflows from protostars of all masses. This latest kinematic result
adds to a growing body of evidence that intermediate-mass star formation
proceeds like a scaled-up version of the formation of low-mass stars.
