Internal visual extinction in Planetary Nebulae
Received 20 October 1997 / Accepted 23 February 1998
Except for a very few planetary nebulae, it is usually assumed that intrinsic extinction in such sources is comparatively small, and may be ignored. Such an assumption underpins all previous estimates of nebular distance employing the so-called "extinction" method. We here suggest that extinction may in fact be appreciable for sources having radii , and rise to where . Such trends are shown to be in reasonable agreement with a simple model of nebular extinction.
Key words: dust; extinction; planetary nebulae; survey
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© European Southern Observatory (ESO) 1998
Online publication: July 27, 1998