This false-color image from NASA's Spitzer Space Telescope shows a dying
star (center) surrounded by a cloud of glowing gas and dust. Thanks to
Spitzer's dust-piercing infrared eyes, the new image also highlights a
never-before-seen feature -- a giant ring of material (red) slightly
offset from the cloud's core. This clumpy ring consists of material that
was expelled from the aging star.
The star and its cloud halo constitute 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's fiery surface, producing huge, glowing clouds -- planetary
nebulas -- that look like giant jellyfish in space.
In this image, the expelled gases appear green, and the ring of expelled
material appears red. Astronomers believe the ring is likely made of
hydrogen molecules that were ejected from the star in the form of atoms,
then cooled to make hydrogen pairs. The new data will help explain how
planetary nebulas take shape, and how they nourish future generations of
stars.
This image composite was taken on Dec. 6, 2003, by Spitzer's infrared
array camera, and is composed of images obtained at four wavelengths:
3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8
microns (red).
