[img]http://www.nasa.gov/images/content/665773main_image_2302_946-710.jpg[/img]



Camelopardalis, or U Cam for
short, is a star nearing the end of
its life. As stars run low on fuel,
they become unstable. Every few
thousand years, U Cam coughs
out a nearly spherical shell of gas
as a layer of helium around its
core begins to fuse. The gas
ejected in the star’s latest
eruption is clearly visible in this
picture as a faint bubble of gas
surrounding the star.
U Cam is an example of a carbon
star, a rare type of star with an
atmosphere that contains more
carbon than oxygen. Due to its
low surface gravity, typically as
much as half of the total mass of
a carbon star may be lost by way
of powerful stellar winds.
Located in the constellation of
Camelopardalis (The Giraffe), near
the North Celestial Pole, U Cam
itself is much smaller than it
appears in this Hubble image. In
fact, the star would easily fit
within a single pixel at the center
of the image. Its brightness,
however, is enough to saturate
the camera's receptors, making
the star look much larger than it
is.
The shell of gas, which is both
much larger and much fainter
than its parent star, is visible in
intricate detail in Hubble’s
portrait. This phenomenon is
often quite irregular and
unstable, but the shell of gas
expelled from U Cam is almost
perfectly spherical.
Image Credit: ESA/NASA