new image from NASA's Spitzer Space Telescope shows the shimmering embers of a dying star, and in their midst a mysterious doughnut-shaped ring
A new image from NASA's Spitzer Space Telescope shows the shimmering embers
of a dying star, and in their midst a mysterious doughnut-shaped ring.
The star is part of a "planetary nebula" called NGC 246. When a star like our
own Sun begins to run out of fuel, its core shrinks and heats up, boiling off
the star's outer layers. Leftover material shoots outward, expanding in shells
around the star. This ejected material is then bombarded with ultraviolet light
from the central star, producing the huge, glowing clouds.
The name "planetary nebula" came from early astronomers who thought the rounded
clouds looked like planets. They last a few thousand years (compared with the
10 billion years or so that a Sun-like star lives).
NGC 246 is located 1,800 light-years away.
In the new false-color picture, released this week, the ring appears clumpy
and red and off-center from the central star, while fluorescent, or ionized,
gases are green. The central star is the left white spot in the middle of the
cloud.
"Although previous observations showed the nebula had a patchy appearance,
Spitzer has revealed a ring component of this dying star, possibly consisting
of hydrogen molecules," said Joseph Hora of the Harvard-Smithsonian Center for
Astrophysics. "The composition of the ring and how it formed are mysteries we
hope to address with further Spitzer studies."
-- SPACE.com Staff
Credit: NASA/JPL/Caltech
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