APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

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APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

Post by APOD Robot » Sun Jun 11, 2017 4:05 am

Image IC 418: The Spirograph Nebula

Explanation: What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 was probably a well-understood star similar to our Sun. Only a few thousand years ago, IC 418 was probably a common red giant star. Since running out of nuclear fuel, though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star, visible in the image center. The light from the central core excites surrounding atoms in the nebula causing them to glow. IC 418 lies about 2000 light-years away and spans 0.3 light-years across. This false-color image taken from the Hubble Space Telescope reveals the unusual details.

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Re: APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

Post by Case » Sun Jun 11, 2017 11:07 am

The inner blueish part of the spirograph could suggest it might be a a second wave, perhaps less intense than the previous outburst, and it somewhat resembles the Cat’s Eye Nebula, with the overlapping oval shapes.

Would we be looking through a cylinder of this PN, or is it likely more like a bubble sphere?

BeeWeeDee

Re: APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

Post by BeeWeeDee » Sun Jun 11, 2017 1:29 pm

0.3 light years - it would be interesting and thought provoking to see our planetary system superimposed on the image at the same scale.

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Re: APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

Post by Chris Peterson » Sun Jun 11, 2017 1:39 pm

BeeWeeDee wrote:0.3 light years - it would be interesting and thought provoking to see our planetary system superimposed on the image at the same scale.
Well, 0.3 ly is about 20,000 AU. Neptune is 30 AU from the Sun. So the standard textbook illustration of the Solar System would occupy a pixel or two at the center of the image. But if we look at our entire system to the edge of the Oort cloud, it would be on the order of ten times larger than this nebula.
Chris

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Re: APOD: IC 418: The Spirograph Nebula (2017 Jun 11)

Post by Boomer12k » Mon Jun 12, 2017 12:33 am

It would appear to be a Planetary Nebula still in its infancy. (only a few thousand years old)...That means, more compact, closer together. As the material expands and thins out, it produces filaments. Plus there are shock waves, and light from the star hitting everything, so it shows variations in the density of the materials, kind of "back-lit".

My guess...

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