A Study of H2 Emission in the Bipolar Proto-Planetary Nebula IRAS 17150-3224
Kwok, Sun; Hrivnak, Bruce J.; Su, Kate Y. L.; Sahai, Raghvendra; Kelly, Douglas M.
United States, Hong Kong SAR, Canada
Abstract
H2 emission 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 H2 1-0 S(1) line has a velocity width of about 35 km s-1 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.
This work was based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.