by APOD Robot » Fri Aug 31, 2012 4:06 am
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 tantalizing image, processed to reveal the enormous but extremely faint halo of gaseous material, about 6
light-years across, which surrounds the brighter, familiar
planetary nebula. Made with narrow and broadband data the composite picture shows the remarkably strong extended emission from twice ionized oxygen atoms in blue-green hues and ionized hydrogen and nitrogen in red.
Planetary nebulae have long been appreciated as a final phase
in the life of a sun-like star. But recently many planetaries have 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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[url=http://apod.nasa.gov/apod/ap120831.html][img]http://apod.nasa.gov/apod/calendar/S_120831.jpg[/img] [size=150]Halo of the Cat's Eye[/size][/url]
[b] Explanation: [/b] The [url=http://apod.nasa.gov/apod/ap110424.html]Cat's Eye Nebula[/url] (NGC 6543) is one of the best known planetary nebulae [url=http://apod.nasa.gov/apod/ap110218.html]in the sky[/url]. Its haunting [url=http://apod.nasa.gov/apod/ap080804.html]symmetries[/url] are seen in the very central region of [url=http://www.astrodonimaging.com/gallery/display.cfm?imgID=255]this tantalizing image[/url], processed to reveal the enormous but extremely faint halo of gaseous material, about 6 [url=http://chandra.harvard.edu/photo/cosmic_distance.html]light-years[/url] across, which surrounds the brighter, familiar [url=http://en.wikipedia.org/wiki/Planetary_nebula]planetary nebula[/url]. Made with narrow and broadband data the composite picture shows the remarkably strong extended emission from twice ionized oxygen atoms in blue-green hues and ionized hydrogen and nitrogen in red. [url=http://www.noao.edu/jacoby/pn_gallery.html]Planetary nebulae[/url] have long been appreciated as a final phase [url=http://imagine.gsfc.nasa.gov/docs/teachers/lifecycles/stars.html]in the life[/url] of a sun-like star. But recently many planetaries have 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 [url=http://www.astro.washington.edu/balick/WFPC2/]planetary nebula phase[/url] is thought to last for around 10,000 years, astronomers estimate the age of the [url=http://www.spacetelescope.org/videos/heic0414a/]outer filamentary portions[/url] of this halo to be 50,000 to 90,000 years.
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