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Credit: Drew Sullivan
(Ancient Starlight)
Explanation:
Why is the
Horsehead Nebula surrounded by a bubble?
Although hard to make out above, the famous
Horsehead Nebula is the slight
dark indentation in the bright streak just to the left
of the image center.
Glowing like an
emission nebula, the origin of the
bubble, known as
Barnard's Loop, is currently unknown.
Progenitor hypotheses include the
winds
from bright Orion stars and the
supernovas
of stars long gone.
Barnard's Loop is too faint to be
identified with the unaided eye.
The nebula
was discovered only in 1895 by
E. E. Barnard on long duration film exposures.
The above image was taken in a single
specific color emitted
by
hydrogen to bring out detail.
To the left of the
Horsehead Nebula,
visible as a small dark indentation, is the photogenic
Flame Nebula, while the textured area just below it is
the Foxfur Nebula.
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NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Horsehead Nebula - emission nebula
Publications with words: Horsehead Nebula - emission nebula
See also: