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Дата изменения: Thu Jul 28 13:17:25 2005
Дата индексирования: Sat Dec 29 07:49:19 2007
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Spherical Planetary Nebula Abell 39
Astronomy Picture of the Day
    


Spherical Planetary Nebula Abell 39
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Spherical Planetary Nebula Abell 39
Credit: Jim Misti (Misti Mountain Observatory)
Explanation: Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules. Abell 39 is a planetary nebula, formed as a once sun-like star's outer atmosphere was expelled over a period of thousands of years. Still visible, the nebula's central star is evolving into a hot white dwarf. Although faint, the nebula's simple geometry has proven to be a boon to astronomers exploring the chemical abundances and life cycles of stars. In this deep image recorded under dark night skies, very distant background galaxies can be found -- some visible right through the nebula itself.

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: planetary nebula - stellar evolution - white dwarf - Abell 39
Publications with words: planetary nebula - stellar evolution - white dwarf - Abell 39
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