Rigel and the Witch Head Nebula
Image Credit &
Copyright:
Rogelio Bernal Andreo
(Deep Sky Colors)
Double,
double toil and trouble;
Fire burn, and cauldron bubble -- maybe
Macbeth should have consulted the Witch Head Nebula.
The suggestively shaped
reflection nebula
is associated with the
bright
star Rigel in the constellation Orion.
More formally known as
IC 2118,
the Witch Head Nebula spans about 50 light-years and
is composed of interstellar dust grains
reflecting Rigel's
starlight.
In this cosmic portrait,
the blue color of the Witch Head Nebula and of the dust surrounding
Rigel
is caused not only by
Rigel's intense
blue starlight but because the
dust grains scatter blue light more efficiently than red.
The same
physical process causes
Earth's daytime sky to appear blue, although the scatterers in
Earth's atmosphere are molecules of
nitrogen and oxygen.
Rigel, the Witch Head Nebula,
and gas and dust that surrounds them lie about 800 light-years away.