  Long slit spectra of the molecular outflow Herbig-Haro (HH) 46/47 has been
taken in the J and K near-infrared bands. The observed H2 line emission
confirms the existence of a bright and extended redshifted counter-jet outflow
southwest of HH46. We show that this outflow seems to be composed of two
different emission regions which have distinct heliocentric velocities, in
contrast with the optical appearance, and which implies an acceleration of the
counter-jet. The observed [FeII] emission suggests an average extinction of 7-9
visual magnitudes for the region associated with the counter-jet. Through
position-velocity diagrams, we show the existence of different morphologies for
the H2 and [FeII] emission regions in the northern part of the HH46/47 outflow.
We have detected for the first time high velocity (-250 Km/s) [FeII] emission
in the region bridging HH46 to HH47A. The two strong peaks detected can be
identified with the optical positions B8 and HH47B. The H2 excitation diagrams
for the counter-jet shock suggest an excitation temperature for the gas of Tex
approx. 2600K. The lack of emission from the higher energy H2 lines such as the
4-3S(3) transition, suggests a thermal excitation scenario for the origin of
the observed emission. Comparison of the H2 line ratios to various shock models
yielded useful constraints about the geometry and type of these shocks. Planar
shocks can be ruled out whereas curved or bow-shocks (both J and C-type) can be
parametrised to adjust our data.
