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Cygnus
Loop
Supernova
Remnant
This
1991 image
from
NASA's
Hubble
Space
Telescope
captures a
small
section of
the Cygnus
Loop
supernova
remnant.
The Cygnus
Loop marks
the edge
of a
bubble-like,
expanding
blast wave
from a
colossal
stellar
explosion
which
occurred
about
15,000
years ago.
Supernova
remnants
play an
important
role in
stellar
evolution
by
enriching
space with
heavy
elements,
and
triggering
new star
formation
by
compressing
interstellar
gas.
The image
shows the
structure
behind the
shock
waves in
the Cygnus
Loop with
unprecedented
clarity,
allowing
astronomers
to compare
directly
the actual
structure
of the
shock with
theoretical
model
calculations
for the
first
time.
Besides
supernova
remnants,
these
shock
models are
important
in
understanding
a wide
range of
astrophysical
phenomena,
ranging
from winds
in
newly-formed
stars to
cataclysmic
stellar
outbursts.
As the
supernova
blast wave
slams into
tenuous
clouds of
interstellar
gas, the
resulting
collision
heats and
compresses
the gas,
causing it
to glow.
The shock
acts as a
searchlight
by
revealing
the
structure
of the
interstellar
medium.
A bluish
ribbon of
light
stretching
left to
right
across the
picture
might be a
knot of
gas
ejected by
the
supernova.
This
interstellar
"bullet,"
traveling
over three
million
miles per
hour (5
million
km), is
just
catching
up with
the shock
front,
which has
been
slowed by
plowing
into
interstellar
material.
The Cygnus
Loop
appears as
a faint
ring of
glowing
gases
about
three
degrees
across
(six times
the
diameter
of the
full
moon),
located in
the
northern
constellation
Cygnus the
Swan. The
supernova
remnant is
within the
plane of
our Milky
Way Galaxy
and is
2,600
light-years
away. |
