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Астронет: Астрономическая картинка дня Ригель и туманность Голова Ведьмы http://www.variable-stars.ru/db/msg/1805534/eng |
Credit & Copyright: Josц Mtanous
Explanation:
By starlight this eerie visage shines in the dark,
a crooked profile evoking its popular name, the
Witch Head Nebula.
In fact, this entrancing
telescopic portrait gives the impression that
the witch has fixed her gaze on Orion's bright supergiant
star Rigel.
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.
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.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.