Searching for Jets in Asymmetrical Nebulae with the Hubble Space Telescope.pdf

Asymmetrical Planetary Nebulae II: From Origins to Microstructures ASP Conference Series, Vol. XXX , 2000 J.H. Kastner, N. Soker, S. Rappaport, eds. Searching for Jets in Asymmetrical Nebulae with the Hubble Space Telescope J. Patrick Harrington Department of Astronomy, University of Maryland, College Park, 9 Maryland 20742 9 9 Kazimierz J. Borkowski 1 t Department of Physics, North Carolina State University, Raleigh, North c Carolina 27695 O 1 Abstract. The jets seen in NGC 6543 motivated us to search for sim- ilar features in other PNe. Our HST snapshot program looked for jets 1 using the [N II] and Hα narrow-band filters. Although spectacular jets v 2 are found in proto-PNe, true jets seem rare among mature PNe. In the 2 later group, IC 4593 is the best case in our sample. We distinguish be- 0 tween jets and a number of interesting “jet-like” features, e.g., “cometary” 0 structures with a dense globule at the end facing the central star. 1 9 9 / h 1. Introduction p - o Observations of Herbig-Haro objects like HH30 and HH34 have provided perhaps r t the best images of narrow, continuous jets. These jets are known to originate in s a the accretion disks surrounding the associated T-Tauri stars. Recently, morpho- : logical studies of PNe have revealed many “point-symmetric” structures, which v i would have a natural explanat