IC 5217 - Planetary Nebula
IC 5217 is a planetary nebula (PN) located at a relatively large distance of 8,200 light-years in the constellation "Lacerta". It was discovered in 1905 by the
American-Scottish astronomer Williamina Fleming, who is also the discoverer of the famous Horsehead Nebula. With an apparent magnitude of 11.3mag
and a diameter of 15", IC 5217 is visible even in smaller telescopes.
The PN features a very narrow equatorial ring, open bipolar wings, and a double envelope, although the ring seems to be rather a very flat disk. So, all in
all, IC 5217 has quite a complex structure. About the known distance the diameter can be determined to 0.6 light years. The expansion velocity is 10...27
kilometers per second in the ring and up to 400km/s at the poles.
The central star (ZS) is 15.5mag bright and belongs to the group of white dwarfs, but still shows a WR characteristic. With a surface temperature of 95,000
Kelvin it is quite hot and therefore able to ionize the nebula's gas envelope and make it glow.
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In my 20" f/3 telescope IC 5217 appears quite bright, but also very small. However, thanks to its high surface brightness, the PN magnifies well to 270x.
The envelope appears oval, but otherwise featureless and homogeneous. Color is not visible either.
In the center the central star flashes faintly with indirect vision from time to time.
