When I first viewed and imaged the fantastic Owl Nebula (M97), it seemed to be a unique object. However, much to my surprise, I have discovered in the years since that a few other PNe have a similar look to the Owl (although in less detail, since they are located further away). This poster shows 6 PNe which I view as “Owl-type” planetary nebulae, similar in structure and formation to M97.
At first, these nebulae appear to be bi-polar, like most pN. But examining their disks carefully, it seems likely that the Owl-type PNe have spherical shapes - they are almost exactly circular in shape and uniform in brightness, with no strong brightening near the rim. The dark void areas are what trick us, in terms of creating a “bi-polar” look. Scientists still do not understand the cause of the bi-polar look to the dark voids.
The PNe on this poster have all (or at least most) of the following characteristics:
- Dominant OIII signal
- Spherical shape (circular in projection)
- Occluded disk
- Dim central star (CSPN)
- No strong rim
- Bi-polar appearance of void regions, which are usually located off-center
There are many other nebulae which have some of these traits, but the 7 on the poster appear to be the result of a similar formation process. I am sure there are other PNe like them in the sky which I have not yet imaged.
If you would like to read more about any of these objects, each of the objects in the poster has previously been uploaded and described individually on Astrobin. They all reside in my
Astrobin PN - Owl-Type Collection.
If you would like to access all my DSO compilation posters, please click
here.
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