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Transcript
Planetary Nebula
Abell 21
Medusa Nebula
Abell 21 is a large planetary nebula
located about 1,500 light-years away in
Gemini. It was originally discovered in
1955 by UCLA astronomer George O.
Abell, who classified it as an old
planetary nebula. The braided serpentine
filaments of glowing gas suggests the
serpent hair of Medusa found in ancient
Greek mythology.
Planetary Nebula
ESO 172-7
Boomerang Nebula
This reflecting cloud of dust and gas has
two nearly symmetric lobes of matter
that are being ejected from a central star.
Each lobe of the nebula is nearly one
light-year in length, making the total
length of the nebula half as long as the
distance from our Sun to our nearest
neighbor - Alpha Centauri.
The Boomerang Nebula is located about
5,000 light-years from Earth in the
direction of the Southern constellation
Centaurus.
Planetary Nebula
HD 44179
Red Rectangle Nebula
Hubble's sharp pictures show that the Red
Rectangle is not really rectangular, but has an
overall X-shaped structure, which the
astronomers interpret as arising from
outflows of gas and dust from the star in the
center. The outflows are ejected from the star
in two opposing directions, producing a shape
like two ice-cream cones touching at their
tips.
This infrared source lies about 2,300 lightyears from Earth in the direction of the
constellation Monoceros. Stars surrounded by
clouds of dust are often strong infrared
sources because the dust is heated by the
starlight and radiates long-wavelength light.
Planetary Nebula
Hubble 5
Double Bubble Nebula
Hubble 5 is a striking example of a
"butterfly" or bipolar (two-lobed) nebula.
The heat generated by fast winds causes
each of the lobes to expand, much like a
pair of balloons with internal heaters.
Planetary Nebula
IC 418
Spirograph Nebula
Glowing like a multi-faceted jewel, this
image from Hubble reveals some
remarkable textures weaving through the
nebula - their origins still uncertain. Over
the next several thousand years, the
nebula will gradually disperse into space;
the white dwarf star will cool and slowly
fade away, taking billions of years. Our
Sun is expected to undergo a similar fate,
but fortunately this will not occur until
some 5 billion years from now.
IC 418 lies about 2,000 light-years from
Earth in the direction of the constellation
Lepus.
Planetary Nebula
IC 3568
Lemon Slice Nebula
IC 3568 is an example of a round
planetary nebula with a bright inner shell
and fainter, smooth, circular outer
envelope. The Lemon slice nebula is one
of the most simple nebulae known, with
an almost perfectly spherical shape. It
appears very similar to a lemon for which
it is named. The central star is a very hot
and bright Red Giant, and can be seen as
a red-orange hue.
IC 3568 lies in the constellation
Camelopardalis at a distance of about
9,000 light-years.
Planetary Nebula
IC 4406
Retina Nebula
Like many other planetary nebulae, IC
4406 exhibits a high degree of symmetry;
the left and right halves are nearly mirror
images of the other. If we could fly
around IC 4406 in a starship, we would
see that the gas and dust form a vast
donut of material streaming outward
from the dying star. This Hubble side view
allows us to see the intricate tendrils of
dust that have been compared to the
eye's retina.
One of the most interesting features of IC
4406 is the irregular lattice of dark lanes
that criss-cross the center of the nebula.
These lanes are about 160 au wide.
Planetary Nebula
M2-9
Butterfly Nebula
Stars transform themselves from normal
stars to white dwarfs by casting off their
outer gaseous envelopes. In the center of
M2-9, two stars orbit inside a gaseous
disk 10 times the diameter of Pluto’s
orbit. The expelled envelope of the dying
star breaks out from the disk creating the
bipolar appearance.
M2-9 is 2,100 light-years away in the
constellation Ophiucus.
Planetary Nebula
M27
Dumbbell Nebula
Like other nebula of its type, M27 is a
bubble of gas that has been ejected by a
star at the end if its life. The core of the
star still remains in the center (the
slightly blue-ish star in the center above
the small triangle of white stars) and
makes this gas bubble glow.
M27 is estimated to be 3,500 years old
and about 1,000 light years away toward
the constellation Vulpecula.
Planetary Nebula
M57
Ring Nebula
This image from Hubble shows a dying
star floating in a blue haze of hot gas.
Surrounding the star is a barrel of gas
that forms a “ring” around the star. The
photo reveals elongated dark clumps of
material embedded in the gas at the
edge of the nebula.
The nebula is about a light-year in
diameter and is located some 2,000 lightyears away in the direction of the
constellation Lyra.
Planetary Nebula
MyCn 18
Hourglass Nebula
This Hubble image reveals the hourglass
shape of MyCn18 with an intricate
pattern of "etchings" in its walls.
Scientists believe the hourglass shape is
produced by the expansion of a fast
stellar wind within a slowly expanding
cloud which is more dense near its
equator than near its poles. The hot star
which has been thought to eject and
illuminate the nebula, and therefore
expected to lie at its center of symmetry,
is clearly off center. An unseen
companion star may be the explaination
for the structure.
MyCn18 is located about 8,000 lightyears away.
Planetary Nebula
Menzel 3 or Mz 3
Ant Nebula
From ground-based telescopes, the "ant
nebula" (Menzel 3, or Mz 3) resembles
the head and thorax of a garden-variety
ant. This Hubble image, showing 10 times
more detail, reveals the "ant's" body as a
pair of fiery lobes protruding from a
dying, Sun-like star.
How does a spherical star produce such a
non-spherical symmetry in the gas that it
ejects? Scientists think perhaps a closely
orbiting companion star exerts strong
gravitational tidal forces, which shape the
out-flowing gas, or possibility, as the
dying star spins, its strong magnetic fields
are wound up into complex shapes.
Planetary Nebula
NGC 2237
Rosette Nebula
Inside the Rosette Nebula lies a cluster of
bright, massive, young stars whose strong
stellar winds and radiation have cleared a hole
in the nebula's center. Ultraviolet light from
these hot stars excites the surrounding
nebula, causing it to glow. Star formation is
still active around the nebula, as proven by
the presence of a very young infrared star
(AFGL 961) still in its final stages of formation.
The young massive stars in the nebula will one
day blow all the gas and dust away.
The Rosette nebula is about 4,500 light-years
away, in the direction of the constellation of
Monoceros.
Planetary Nebula
NGC 2392
Eskimo Nebula
In this Hubble image, the "parka" is really a
disk of material embellished with a ring of
comet-shaped objects, with their tails
streaming away from the central, dying star.
The bright central region, resembling a ball of
twine, is a bubble of material being blown
into space by the central star’s intense “wind”
of high-speed material. The nebula's glowing
gases produce the colors in this image:
nitrogen (red), hydrogen (green), oxygen
(blue), and helium (violet).
The Eskimo Nebula is about 5,000 light-years
from Earth in the constellation Gemini.
Planetary Nebula
NGC 2440
NGC 2440 is another planetary nebula
ejected by a dying star. The central star of
NGC 2440 is one of the hottest known
with a surface temperature near 200,000
degrees Celsius. The nebula is also rich in
clouds of dust, some of which form long,
dark streaks pointing away from the
central star.
NGC 2440 lies about 4,000 light years
from Earth.
Planetary Nebula
NGC 2818
The spectacular structure of NGC 2818
contains the outer layers of a star that
were expelled into interstellar space. The
glowing gaseous shrouds in the nebula
were shed by the central star after it ran
out of fuel to sustain the nuclear
reactions in its core. Planetary nebulae
fade gradually over tens of thousands of
years. The hot remnant stellar core of
NGC 2818 will eventually cool off for
billions of years as a white dwarf.
NGC 2818, which lies in the southern
constellation of Pyxis (the Compass).
Planetary Nebula
NGC 3132
Eight-Burst or Southern Ring Nebula
It’s the dim star, not the bright one, near
the center of NGC 3132 that created this
odd but beautiful planetary nebula. The
pool of light seen surrounding this binary
system is energized by the hot surface of
the faint star. Blue represents the hottest
gas, which is confined to the inner region
of the nebula. Red represents the coolest
gas, at the outer edge.
NGC 3132 is nearly half a light year in
diameter, and at a distance of about 2000
light years is one of the nearer known
planetary nebulae. The gases are
expanding away from the central star at a
speed of 9 miles per second.
Planetary Nebula
NGC 3242
Ghost of Jupiter Nebula
A notable feature of the nebula is the
presence of the two red 'fliers' on both
poles of the nebula. The gas comprising
these objects is believed to be younger
and moving at a much faster rate than
that of the nebula.
It is also sometimes referred to
as the Eye Nebula.
Planetary Nebula
NGC 3918
Blue Planetary Nebula
In the center of the cloud of gas, and
completely dwarfed by the nebula, are
the dying remnants of a red giant. During
the final convulsive phase in the
evolution of these stars, huge clouds of
gas are ejected from the surface of the
star before it emerges from its cocoon as
a white dwarf.
Planetary nebula NGC 3918 is about 4900
light-years from Earth in the
constellation of Centaurus.
Planetary Nebula
NGC 5189
Spiral Planetary Nebula
A spectacular example of the final stages
in the life of a medium-sized star can be
seen in the beautiful complexity of the
bluish lobes of NGC 5189.
As a result of the mass-loss process, the
planetary nebula has been created with
two nested structures, tilted with respect
to each other, that expand away from the
center in different directions. The bright
golden ring that twists and tilts through
the image is made up of a large collection
of radial filaments and cometary knots.
These are usually formed by the
combined action of photo-ionizing
radiation and stellar winds.
Planetary Nebula
NGC 5307
Spiral-Structured Planetary Nebula
Some stellar nebulae are strangely
symmetric. NGC 5307 is an example of a
planetary nebula with a spiral shape.
Spiral planetary nebulae are thought to
be caused by a bright central white dwarf
star expelling a symmetric wobbling jet of
rapidly moving gas.
NGC 5307 lies in Centaurus and is about
10,000 light-years away and has a
diameter of approximately 0.6 light-year.
Planetary Nebula
NGC 6302
Bug Nebula or Butterfly Nebula
What resemble dainty butterfly wings are
actually roiling cauldrons of gas heated to
more than 36,000 degrees Fahrenheit.
The gas is tearing across space at more
than 600,000 miles an hour -- fast
enough to travel from Earth to the moon
in 24 minutes! The star’s surface
temperature is estimated to be about
400,000 degrees Fahrenheit, making it
one of the hottest known stars in our
galaxy.
NGC 6302 lies roughly 3,800 light-years
away in the constellation Scorpius.
Planetary Nebula
NGC 6537
Red Spider Nebula
The Red Spider Nebula is a planetary nebula
located in the constellation Sagittarius. The
star at the center of the nebula is surrounded
by a dust shell making its exact properties
hard to determine. The nebula has a
prominent two-lobed shape, possibly due to a
binary companion or magnetic fields.
The central white dwarf, the remaining
compact core of the original star, produces a
powerful and hot wind blowing with a speed
of 300 km/sec, which has generated waves
100 billion kilometers high. These winds are
what give this nebula its unique 'spider' shape
and also contribute to the expansion of the
nebula.
Planetary Nebula
NGC 6543
Cats Eye Nebula
The Hubble telescope has made several
observations of the Cat’s Eye. This image
reveals the full beauty of a bull’s eye
pattern of 11 or more concentric rings, or
shells, around the dying star. Each ring is
actually the edge of a spherical bubble
seen projected onto the sky — that is
why the nebula appears bright along its
outer edge.
Planetary Nebula
NGC 6751
Glowing Eye Nebula
The Glowing Eye Nebula is a beautiful
example of a classic planetary nebula
with complex features. Winds and
radiation from the intensely hot central
star (140,000 degrees Celsius) have
apparently created the nebula’s
streamer-like features.
Blue regions mark the hottest glowing
gas, which forms a roughly circular ring
around the central stellar remnant.
Orange and red show the locations of
cooler gas. The cool gas tends to lie in
long streamers pointing away from the
central star, and in a surrounding,
tattered-looking ring at the outer edge of
the nebula.
Planetary Nebula
NGC 6826
The Blinking Eye Nebula
NGC 6826's eye-like appearance is
marred by two sets of blood-red 'fliers'
that lie horizontally across the image. The
surrounding faint green 'white' of the eye
is believed to be gas that made up almost
half of the star's mass for most of its life.
The hot remnant star (in the centre of
the green oval) drives a fast wind into
older material, forming a hot interior
bubble which pushes the older gas ahead
of it to form a bright rim.
NGC 6826 is 2,200 light- years away in
the constellation Cygnus.
Planetary Nebula
NGC 7008
Fetus Nebula
Observers have long been aware of the unique
structure of planetary nebula NGC 7008. Because
the central star is so prominent, the original
thinking on this nebula’s formation focused around
the central star itself. But the motions of the gas are
also being observed and a recent study suggest that
some of the structures observed are caused by the
interaction of central star wind and radiation with
preplanetary nebula debris: planets, moons, minor
objects and ring and ring arcs. If there are massive
enough rings of material surrounding the progenitor
and planets in their vicinity, arc rings could be
formed. f the rings are viewed pole on when the
envelope is detached from the central star, it will
interact with the arc ring material and could
produce ansae and pedal and garden-hose-shape.
NGC 7008 (PK 93+5.2), also known as the Fetus
Nebula is located at a distance of 2800 light years in
northern Cygnus.
.
Planetary Nebula
NGC 7009
Saturn Nebula
NGC 7009 has a bright central star at the
center of a dark cavity bounded by a
football-shaped rim of dense, blue and
red gas. The cavity and its rim are
trapped inside smoothly-distributed
greenish material in the shape of a barrel
and comprised of the star's former outer
layers. At larger distances, and lying along
the long axis of the nebula, a pair of red
"ansae", or "handles" appears. Each ansa
is joined to the tips of the cavity by a long
greenish jet of material. The handles are
clouds of low-density gas. NGC 7009 is
1,400 light-years away in the
constellation Aquarius.
Planetary Nebula
NGC 7027
NGC 7027 is one of the brightest
planetary nebulae in the sky and can be
seen in the constellation of the Cygnus.
The cloud of gas and dust is unusually
massive as it appears to contain about
three times the mass of our Sun.
Planetary Nebula
NGC 7293
Helix Nebula
The image shows a fine web of
filamentary "bicycle-spoke" features
embedded in the colorful red and blue
gas ring, which is one of the nearest
planetary nebulae to Earth. The tentacles
formed when a hot "stellar wind" of gas
plowed into colder shells of dust and gas
ejected previously by a doomed star.
Planetary Nebula
NGC 7293
Helix Nebula
This is a combined image from Spitzer Space
Telescope and the Galaxy Evolution Explorer
(GALEX).
The intense ultraviolet radiation from the
white dwarf heats up the expelled layers of
gas, which shine brightly in the infrared. GALEX
has picked out the ultraviolet light pouring out
of this system, shown throughout the nebula
in blue, while Spitzer has snagged the detailed
infrared signature of the dust and gas in
yellow. The white dwarf star itself is a tiny
white pinprick right at the center of the
nebula.
Helix nebula lies 650 light-years away in the
constellation of Aquarius.
Planetary Nebula
PK 164+31.1
Jones-Emberson 1 Nebula
This bubble of expanding gas is the
remnant of the atmosphere of a Sun-like
star expelled as its supply of fusion-able
core hydrogen became depleted. Visible
near the center of the nebula is what
remains of the core itself -- a blue-hot
white dwarf star.
PK 164 +31, also known as JonesEmberson 1, lies about 1,600 light years
away toward the constellation of Lynx.
Planetary Nebula
RAFGL 2688
Egg Nebula
Resembling a rippling pool illuminated by
underwater lights, the Egg Nebula offers
astronomers a special look at the
normally invisible dust shells swaddling
an aging star. These dust layers,
extending over one-tenth of a light-year
from the star, have an onionskin
structure that forms concentric rings
around the star. A thicker dust belt,
running almost vertically through the
image, blocks off light from the central
star.
The Egg Nebula is located 3,000 lightyears away in the constellation Cygnus.
Planetary Nebula
OH231.8+4.2
Rotten Egg Nebula
The object shown in this Hubble image is a
remarkable example of a star going through
death throes just as it dramatically transforms
itself from a normal red giant star into a
planetary nebula. This process happens so
quickly that such objects are quite rare, even
though astronomers believe that most stars
like the Sun will eventually go through such a
phase.
OH231.8+4.2, is seen blowing out gas and
dust in two opposite directions. So much dust
has been cast off and now surrounds the star
that it cannot be seen directly, only its
starlight that is reflected off the dust. The flow
of gas is very fast, with a velocity up to
450,000 mph (700,000 km/h).