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Session 114 - Circumstellar Material & Nebulae.
Oral session, Saturday, January 10
The process by which a planetary nebula disolves into the surrounding ISM is dominated by dynamical instabilities. The magnetic field of the ISM destabilizes the inteaction and shapes the nebula to form elongated aligned filaments or stripes. Here I concentrate on the group of interacting planetary nebulae that have stripes. I derive a simple formula that relates the density and orientation of the stripes to the properties of the interaction. In most cases, the direction of the stripes is perpendicular to the direction of the velocity of the nebula. The seperation between adjacent stripes, in units of the radius of the nebula, is related to the ratio of Alfven's speed and the relative velocity of the nebula. Nebulae with higher ratios have thicker stripes.
Program listing for Saturday