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Credit & Copyright: Nik Szymanek
Explanation:
Blown by fast winds from a hot, massive star,
this cosmic bubble is huge.
Cataloged as
Sharpless
2-308 it lies some 5,000 light-years away toward the constellation of
the Big Dog
(Canis
Major) and covers slightly more of the sky than a Full Moon.
That
corresponds
to a diameter of 60 light-years at its estimated distance.
The massive star that created the bubble, a
Wolf-Rayet star,
is the bright one
near the center
of the nebula.
Wolf-Rayet
stars have over 20 times the mass of the Sun
and are thought to be in a brief,
pre-supernova phase
of massive star evolution.
Fast winds from this
Wolf-Rayet
star
create the bubble-shaped nebula as they
sweep up slower moving material from an earlier phase of evolution.
The windblown nebula has an age of about
70,000
years.
Relatively faint emission captured by narrowband filters in the deep image
is dominated by the glow of ionized oxygen atoms
mapped
to
a blue hue.
Presenting a
mostly
harmless
outline, SH2-308 is also known as The Dolphin-head 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: Wolf-Rayet star
Publications with words: Wolf-Rayet star
See also: