Image Credit & Copyright: Don Goldman
Explanation: A mere seven hundred light years from Earth, in the
constellation Aquarius, a sun-like star
is dying. Its last few thousand years have produced the Helix Nebula (NGC
7293), a well studied and nearby example of a Planetary Nebula,
typical of this final phase of stellar evolution. A total of 28.5 hours of
exposure time have gone in to creating this deep view
of the nebula. Combining narrow band image data from emission lines of
hydrogen atoms in red and oxygen atoms in blue-green hues, it shows remarkable
details of the Helix's brighter inner region, about 3 light-years across, but also
follows fainter outer halo features that give the
nebula a span of well over six light-years. The white dot at the Helix's center
is this Planetary Nebula's hot, central
star. A simple looking nebula at first glance,
the Helix is now understood to have a surprisingly complex
geometry.
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