1994A&A...289L..19G

A near-infrared K-band mosaic of the HH 111 system shows a highly collimated infrared counter-flow to the HH 111 jet, on the opposite side of the driving VLA source. Near-infrared long-slit spectra demonstrate that the newly detected knots are emission line objects with no continuum emission. The knots seen in the counter-flow show a strikingly symmetric spatial correspondence to knots seen in the HH 111 jet, making the system the most symmetric bipolar HH flow known. This remarkable symmetry provides evidence that the knots in the jets result from disturbances originating in the energy source, rather than from Kelvin-Helmholtz instabilities in the flow.