COOL IMAGES: Eyes of Flame

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Science  22 Oct 1999:
Vol. 286, Issue 5440, pp. 639
DOI: 10.1126/science.286.5440.639a

Thousands of years ago a dying star coughed up the gases now forming the “white” of this so-called blinking eye nebula, formally known as NGC6826. Now a hot wind from the star's smoldering remnants is pushing a newer bubble of gas into the dissipating older one. Astronomers are still debating the cause of the red streaks shooting from the white of the eye.

This image and nearly 80 more are showcased in the Images of Galactic Planetary Nebulae site compiled by astronomers Arsen Hajian of the U.S. Naval Observatory and Yervant Terzian of Cornell University. These exotic structures got the “planetary” in their name from their relatively bright colors, which reminded early astronomers of planets. In their dying throes, medium-sized stars swell to many times their original size before collapsing under their own gravity into orbs of iron, carbon, and oxygen called white dwarves. Not all matter sticks to the central remnant, however; some bounces off and puffs away to linger as a nebula for tens of thousands of years.

One of astronomy's major riddles, Hajian says, is why these nebulae aren't perfectly round. “There are butterflies, ellipses, footballs, all kinds of goofy shapes,” he says. Researchers have suggested that a Jupiter-sized planet's gravity might stretch a nebula; alternatively, a binary star system or a spinning star could spew out irregularly shaped nebulae. Planetary nebulae foreshadow our own solar system's fate: Five billion years from now, after the bloated sun has incinerated Earth, it should also collapse and spin off a nebula that will be beautiful, perhaps, to the eye of some distant beholder.

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