NGC 2359: Thor's Helmet
From NASA’s Astronomy Picture of the Day
This helmet-shaped
cosmic cloud with wing-like appendages is popularly called Thor's Helmet.
Heroically sized even for a Norse god, Thor's
Helmet is about 30 light-years across.
In fact, the helmet is
more like an
interstellar bubble, blown as a fast wind from the bright, massive star
near the bubble's center sweeps through a surrounding molecular cloud.
Known as a Wolf-Rayet
star, the central star is an extremely hot giant thought to be in a brief,
pre-supernova stage
of evolution.
Cataloged as NGC 2359,
the nebula is located about
15,000 light-years away in the constellation Canis Major.
The sharp image, made
using broadband and narrowband filters, captures striking details of the nebula's filamentary
structures. It shows off a blue-green color from strong emission due
to oxygen atoms in the glowing gas.
Image Credit & Copyright: Bob
and Janice Fera (Fera
Photography)