2006ApJ...650..237H

H₂emission has been detected in the bipolar proto-planetary nebula IRAS 17150-3224 from the 1-0 S(1), 1-0 S(0), and 2-1 S(1) transitions in the 2 µm region. Line ratios suggest that this emission is due to collisional excitation. High-resolution imaging with NICMOS on HST shows that the emission comes from four regions: clumps near the ends of the lobes (the brightest region), the lobes in general, a particular region outside the northwest lobe, and a faint loop in the equatorial region. Spatially resolved high-resolution spectra at 2.12 µm reveal that the H₂1-0 S(1) line has a velocity width of about 35 km/s in the lobes, consistent with C-type shocks. The emission from the clumps in the lobes appears to arise from the impact of a fast wind with the slower moving material in the AGB wind.