2000 September 6
CRL 618 may look to some like an
Olympian
declaring victory.
Only a few hundred years ago, however,
CRL 618 appeared as a relatively modest red giant star.
Since then it has run out of core material to
fuse and so has started to become a
planetary nebula.
In its current
proto-planetary nebula phase,
CRL 618 is evolving quickly,
expelling hot gasses in
complex jets and
rings moving outwards faster
than 700,000 kilometers per hour.
In a few thousand years, the glowing core of the cool
red giant will be bare, revealing a hot
white dwarf star.
Much remains unknown about
planetary nebulae formation,
including details of how geometries like this form.
Perhaps one day some part of this nebula
will be able to declare victory -
CRL 618
has an extraordinary abundance of
carbon-chain molecules.
