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Дата изменения: Sat Feb 24 00:02:30 2007
Дата индексирования: Tue Oct 2 17:14:44 2012
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Поисковые слова: comet tail
APOD: 2007 February 23- Dust and the Helix Nebula
Astronomy Picture of the Day
    


APOD: 2007 February 23- Dust and the Helix Nebula
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APOD: 2007 February 23- Dust and the Helix Nebula
Credit & Copyright: NASA, JPL-Caltech, Kate Su (Steward Obs, U. Arizona) et al.
Explanation: Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Formed in the distant planetary system, the comet-like bodies have otherwise survived even the dramatic late stages of the star's evolution.

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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NASA Official: Jay Norris. Specific rights apply.
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& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: planetary nebula - dust - comet - planetary system
Publications with words: planetary nebula - dust - comet - planetary system
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