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B.J. Hrivnak (Valparaiso U.), N. Smith (U. Colorado), K.Y.L. Su (Steward Obs.)
The shaping of bipolar proto-planetary nebulae is thought to occur as a fast wind from the central star interacts with a circumstellar envelope containing a latitudinal density dependence. But when does this fast wind begin? Collisionally-excited H2 emission in the nebulae can provide a tracer of the fast wind as it interacts with the remnant AGB mass loss which forms the circumstellar envelope. We have carried out a study of the kinematics of the H2 emission in IRAS 16594-4645, Rob 22, and Hen3-401, using high-resolution, long-slit spectra obtained with the Phoenix spectrograph on Gemini-South. All three have bipolar nebulae and in all three the H2 is collisionally-excited. The spatially-resolved spectra are compared with H2 images and a resulting kinematical model developed. This work was supported by grants from the NSF (0407087, BJH) and NASA through STScI (GO-09366.01-A/C, BJH/KYLS; HF-01166.01A, NS).
Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.