APOD: IC 418: The Spirograph Nebula (2010 Apr 11)

[APOD Robot]

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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[tesla]

If you could look at this Nebula from sideways, it would be an hourglass shape. Now if that does not give you a clue as to what is happening,well.....
It has not run out of Nuclear fuel had not and never has run on nuclear fuel. This is an old theory that has shown to be false. Close studies of our own Sun has all but thrown that theory out. "Chaotic winds from the variable central star..." When have you seen winds cause this pattern? Never! If you have a look at it from X rays, that should really show what is happening!

[madtom1999]

The patterns do remind me of ripples on water from sound. I wonder if they might be remnants of some complicated wave pattern from the top of the star as it exploded. A baby big bang perhaps or... Could it even be that something fell into the (relatively inactive) star causing the ripples on the surface and then triggering the detonation leaving those ripples as an image in the expanding gas.

[Nick]

If I can describe the event as having an "outer" and "inner" shell, both seem to be elongated along a similar alignment with the outer shell being "ruptured". Is there some outside event we are not seeing?

[owlice]

Looks to me as though there may be another Eskimo in the making, though what that Eskimo is wearing may be different.

[zbvhs]

It appears to me that what we're seeing is a spheroid of some sort. The yellow stuff forms the surface of the outer shell and is dense enough and bright enough to be visible. Ditto the blue stuff on the inside. Looks to me like both spheroids are being pushed out by mass ejecta and radiation pressure from the star, which appears to be quite hot. The uniformity in the shape of the thing suggests to me that we're not looking at the results of some explosive event.

[ASTRONUT]

WOW! What a Big "Little Beadie Eye". Just goes to show that we never really know who - or what - is watching US!! - and why?

[knill]

The expanding gas shell might have been "spirographed" by an orbiting sister star or planet when the expanding gas cloud diameter was small and as the shock front passed through the orbit of this sister star or planet. Then, the impressed structure might persist in the gas envelope as it expanded further. And, the expanding parent star might have absorbed the sister star or planet as it expanded, leaving no trace. Just a thought....