http://news.bbc.co.uk/hi/english/sci/tech/newsid_1134000/1134888.stm
<<By BBC News Online science editor Dr David Whitehouse
It looks like a gigantic soap bubble floating in space. This is Abell 39, a
remarkably beautiful object that could help astronomers solve problems about
the chemical composition of stars.
The object is an example of a planetary nebula, a shell of material puffed
off by certain stars towards the end of their lives. The name is something of
a misnomer; early astronomers mistakenly thought these objects to be planets.
The symmetry of Abell 39, one of the largest such spheres ever discovered,
enables scientists to make an accurate estimate of how much material is
actually absorbing and emitting light. This will allow its composition to be
determined.
At present, there is a disagreement among astronomers about the exact
chemical make-up of dying stars that produce these planetary nebulae. Abell
39 may help solve this problem.
"The truly spherical nature of this beautiful....>>
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