AAS 201st Meeting, January, 2003
Session 22. Highly Structured Outflows from Post MS-Stars
Special, Monday, January 6, 2003, 10:00-11:30am, 6AB

[Previous] | [Session 22] | [Next]

[22.06] Multipolar structures in planetary nebulae

S. Kwok (University of Calgary)

In addition to the main nebular shells, planetary nebulae (PNe) are now known to possess secondary shell structures called crowns and haloes. These structures can be satisfactorily explained by coupled dynamical and stellar evolutionary models based on the interacting winds scenario. By introducing time-variability in the fast wind, these models also have some success in accounting for other microsctructures such as jets and FLIERs.

A more surprising development has been the discovery of multipolar structures in PNe. A number of bipolar nebulae have been found to have 2 or 3 bipolar axes, sometimes superimposed with multiple 2-dimensional rings and concentric circular arcs. The existence of these features suggests that the fast wind may be changing in direction in addition to varying in magnitude. In this paper, we will summarize the current observations of multipolar nebulae and discuss their possible origins.

This work is supported by the Natural Sciences and Engineering Research Council of Canada, and by a Killam Fellowship from the Canada Council for the Arts.

If you would like more information about this abstract, please follow the link to http://www.iras.ucalgary.ca. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: kwok@iras.ucalgary.ca

[Previous] | [Session 22] | [Next]

Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.