Cygnus Loop
A large nebula in the constellation Cygnus,
some 80 light-years across, lying about 2,500 light-years away and 330 light-years
above the galactic plane, that is
the remains of a supernova explosion inside
another supernova explosion (see also supernova
remnant); the most prominent part of it at visible wavelengths is the
Veil Nebula. The initial supernova took
place roughly 18,000 years ago and sent out powerful shock fronts that propagated
into the interstellar medium, creating a giant
cavity in the surrounding clouds. This was followed by the explosion of
a second massive star, at least 5,000 years ago, shock
waves from which are now interacting with the original cavity walls.
The result of this interaction are ragged, sweeping filaments of denser
interstellar matter that have been energized to the point at which they
radiate at visible wavelengths, together with smoother, more delicate filaments,
at the outer edges of the expanding shock fronts, formed where there the
density of interstellar matter is much lower.
Related
category
• NEBULAE
AND STAR CLUSTERS
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