The most widely accepted classification of PN's was devised by Vorontsov-Velyaminov in 1934. Although there have been alternative classifications proposed, such as Gurzadyan's system, most of the data that I have seen uses the V-V types.
In this system, there are six major
classifications with two of these classes containing sub-types. Depending on the
morphology of the planetary, individual PN's can be typed into more than one major
classification and also sub-types. In my present collection of data, I have
identified at least 35 separate types of planetary form. The classification system
is presented here, and to illustrate this system, I have linked representative images to
the listed type. At present, these images have been downloaded and processed, and
annotated from NASA's SkyView website. It is planned to replace these general sky
images with dedicated images taken of the individual planetaries so that the true
nature of their forms can be instantly recognized. With the SkyView images, it is
not always possible to discern the exact nature of the object since the exposure time,
image scale, and filter's used were not optimum for the object.
The images that I have selected are presented in
'negative' format so that hopefully any faint detail will be more discernable and each
image, unless otherwise noted, has a size of 7.5 arcminutes square.
To view an image, click on the text for each
type.
VORONTSOV-VELYAMINOV PLANETARY NEBULA TYPES:
2.
Smooth Disk (II)
2a. Smooth Disk, brighter towards center. (IIa)
2b. Smooth Disk, uniform brightness. (IIb)
2c. Smooth Disk, traces of ring structure. (IIc)
3.
Irregular Disk (III)
3a. Irregular Disk, very irregular brightness
distribution. (IIIa)
3b. Irregular Disk, traces of ring structure.
(IIIb)
5. Irregular Form, similar to a diffuse nebula. (V)
More complex structure can be categorized by combining the various types, such as 3b+2 (one irregular disk with traces of ring structure, and a second smooth disk), 4+4 (double ring structure), or 4+2 (a ring and a smooth disk present).
With the data that I have gathered, I have found an additional twenty-four combination types of planetaries. These will be added shortly, along with images from SkyView. There is quite a array of forms and structures that exist with planetary nebula, and I hope the images presented are helpful.
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