Astronomy Picture of the Day |
APOD: 2005 June 12 - M2 9: Wings of a Butterfly Nebula
Explanation:
Are stars better appreciated for their art after they die?
Actually, stars usually create their most artistic displays as they die.
In the case of low-mass stars like our
Sun and
M2-9 pictured above, the stars transform themselves from normal stars to
white dwarfs
by casting off their outer gaseous envelopes.
The expended gas frequently forms an impressive display called a
planetary nebula that fades gradually over thousand of years.
M2-9, a butterfly
planetary nebula 2100
light-years away shown in representative colors,
has wings that tell a strange but
incomplete tale.
In the center, two stars orbit inside a
gaseous disk 10 times the orbit of Pluto.
The expelled envelope of the dying star breaks out from the
disk creating the bipolar appearance.
Much remains unknown about the physical processes that cause
planetary nebulae.
APOD: 2003 June 14 - The Planetary Nebula Show
Explanation:
What do the Owl, the Cat's Eye, the Ghost of Jupiter, and Saturn
have in common?
They're all
planetary nebulae
of course, glowing gaseous
shrouds shed by dying sun-like stars
as
they run out of nuclear fuel.
Beautiful to
look at,
the symmetric,
planet-like
shapes of these
cosmic clouds,
typically 1,000 times the size of our
solar system,
evoke their popular names.
Flipping through digital pictures made by
participants in the Kitt Peak
National Observatory Visitor Center's
Advanced Observing Program,
astronomer Adam Block created this
delightful animation.
Ten different planetary nebula images are presented, each registered
on the central star.
In order, their catalog designations are
NGC
1535,
NGC 3242 (Ghost of Jupiter),
NGC 6543 (Cat's Eye),
NGC 7009 (Saturn Nebula),
NGC 2438,
NGC 6772,
Abell 39,
NGC 7139,
NGC 6781,
and M97 (Owl Nebula).
This glorious final phase
in the life of a star lasts only about 10,000 years.
APOD: 2002 November 8 - NGC 6369: The Little Ghost Nebula
Explanation:
This pretty planetary nebula, cataloged as
NGC 6369, was discovered
by 18th century astronomer
William Herschel as he used a
telescope to explore the constellation
Ophiucus.
Round and planet-shaped, the nebula
is also relatively
faint
and has acquired the popular moniker of
Little Ghost Nebula.
Planetary
nebulae in general are
not at all related to planets,
but instead are created at the end of a sun-like star's life as its
outer layers expand
into space while the star's core shrinks to become
a white dwarf.
The transformed white dwarf star,
seen near the center,
radiates strongly at ultraviolet wavelengths and powers the expanding
nebula's glow.
Surprisingly complex
details
and structures of NGC 6369 are revealed in this
delightful
color image composed from Hubble Space Telescope
data.
The nebula's main ring structure is about a light-year across and
the glow from ionized oxygen, hydrogen, and nitrogen atoms
are colored
blue, green, and red respectively.
Over 2,000 light-years away, the
Little Ghost Nebula offers a glimpse
of the fate of our Sun, which should produce its own pretty planetary
nebula only about 5 billion years from now.
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:
EUD at
NASA /
GSFC
& Michigan Tech. U.