APOD: Halo of the Cat's Eye (2020 Jun 07)

[APOD Robot]

Halo of the Cat's Eye

Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows extended emission from the nebula. Planetary nebulae have long been appreciated as a final phase in the life of a Sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years.

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[orin stepanek]

Reminds me of a beautiful flower, burst into bloom!

[Ann]

Hats off...

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...to cat's eyes...

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...nebula...

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...hail! I mean, halo!

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[neufer]

Tweety's debut in 1942's A Tale of Two Kitties (Babbit & Catstello)

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The Cat's Eye Nebula (NGC 6543)'s haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula.

This [NOT in the Canary Islands] composite picture shows extended emission from the nebula.

[Sa Ji Tario]

¿Can anyone explain what the spokes are like Japanese parasol rods seen in some images?

[Ann]

Tweety's debut in 1942's A Tale of Two Kitties (Babbit & Catstello)

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The Cat's Eye Nebula (NGC 6543)'s haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula.

This [NOT in the Canary Islands] composite picture shows extended emission from the nebula.

Copy A of William Blake's original printing of The Tyger, c. 1795. Copy A is held by the British Museum.

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Tyger Tyger, burning bright,
In the forests of the night;
What immortal hand or eye,
Could frame thy fearful symmetry?

Ann

[ecdowney]

If radius is proportional to time back, it looks like at first there was no rotation (outer third), then equal emission in all directions (middle third), and now leisurely rotation (inner third). Is this a correct interpretation? If so, what caused the change in rotation, perhaps asymmetric emission?

[orin stepanek]

Tweety's debut in 1942's A Tale of Two Kitties (Babbit & Catstello)

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The Cat's Eye Nebula (NGC 6543)'s haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula.

This [NOT in the Canary Islands] composite picture shows extended emission from the nebula.

I thaut I saw a putty-cat! I don't think that's Sylvester though!
Sylvester & Tweety today
>

th.jpg (11.62 KiB) Viewed 3856 times

Picture from image results

[ta152h0]

Earth is a product of accretion of particles over a long time. What makes the center of the Earth a fireball? pass the ice cold one

[Ann]

Earth is a product of accretion of particles over a long time. What makes the center of the Earth a fireball? pass the ice cold one

Doesn't it have to do with radioactive decay in the large iron/nickel core of the Earth?

Ann

[johnnydeep]

¿Can anyone explain what the spokes are like Japanese parasol rods seen in some images?

I don't seek "spokes" in this image of the cat's eye nebula, rather, there seem to be net-like filaments of denser gas. Not sure what causes that - perhaps magnetic fields? Or maybe it's just random density variations.

[johnnydeep]

Earth is a product of accretion of particles over a long time. What makes the center of the Earth a fireball? pass the ice cold one

Doesn't it have to do with radioactive decay in the large iron/nickel core of the Earth?

Ann

Yes, plus two other factors. From https://www.scientificamerican.com/arti ... s-core-so/ :

There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.

All three phenomena are pretty amazing to me: that there is heat STILL left over from when the Earth formed 4.5 gys ago; that there is any significant amount of FRICTION caused just by slowly sinking rock; and that the core is full of radioactive elements!

The upshot is that were the sun to go dark, we could still survive for quite a long while by digging deep enough. Or at least we would be nice and warm. There's still the not so minor matters of oxygen and food to worry about

[johnnydeep]

If radius is proportional to time back, it looks like at first there was no rotation (outer third), then equal emission in all directions (middle third), and now leisurely rotation (inner third). Is this a correct interpretation? If so, what caused the change in rotation, perhaps asymmetric emission?

Interesting conjecture. I'm not sure the different appearances of the various layers reflects rotational speed. But, I think it would be true that as material was ejected, it would steal angular momentum from what remained causing it to rotate more slowly?