Year: 2008
Type: article
Abstract: The bipolar planetary nebula NGC 650-1 has been imaged in Hα, Hβ, [N ii]λ6583 Å and [S ii]λλ6717+6731 Å. These results are used to map the variation of extinction over the interior regions of the shell, where we find evidence for a gradual increase in AV between the SW and NE limits of the central emission bar. It is argued that this is likely to arise from dust associated with the nebular envelope itself. We have also produced a map of electron densities over this region, and find evidence for marked variations in ne over a scale of ∼5 arcsec, a variation which is probably related to the clumpy emission structure observed in low-excitation images. We finally present contour mapping of mid-infrared Spitzer images of the source at 3.6, 4.5, 5.8 and 8 μm. These show that the central bar has a more or less uniform emission structure, although with evidence for condensations which are similar to, and in most cases coincidental with, comparable low-excitation structures noted in [N ii]. There is also evidence for an increase in 8/4.5 μm and 5.8/4.5 μm emission ratios with distance from the nucleus, and for an extension of 8 and 5.8 μm emission beyond the ionized regime; a trend which is attributed to strong polycyclic aromatic hydrocarbon band emission within the nebular photodissociative regime.
Authors: G. Ramos-Larios, J. P. Phillips, L. Cuesta
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2124310161