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Crab Nebula Supernova Remnan
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| Title |
Crab Nebula Supernova Remnant (IRAC-MIPS Image) |
| Description |
The Crab Nebula is the shattered remnant of a massive star that ended its life in a massive supernova explosion. Nearly a thousand years old, the supernova was noted in the constellation of Taurus by Chinese astronomers in the year 1054 AD. This view of the supernova remnant obtained by the Spitzer Space Telescope shows the infrared view of this complex object. The blue region traces the cloud of energetic electrons trapped within the star's magnetic field, emitting so-called "synchrotron" radiation. The yellow-red features follow the well-known filamentary structures that permeate this nebula. Though they are known to contain hot gasses, their exact nature is still a mystery that astronomers are examining. The energetic cloud of electrons are driven by a rapidly rotating neutron star, or pulsar, at its core. The nebula is about 6,500 light-years away from the Earth, and is 5 light-years across. This false-color image presents images from Spitzer's Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) at 3.6 (blue), 8.0 (green), 24 (red) microns. |
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Crab Nebula Supernova Remnan
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| Title |
Crab Nebula Supernova Remnant (IRAC Image) |
| Description |
The Crab Nebula is the shattered remnant of a massive star that ended its life in a massive supernova explosion. Nearly a thousand years old, the supernova was noted in the constellation of Taurus by Chinese astronomers in the year 1054 AD. This view of the supernova remnant obtained by the Spitzer Space Telescope shows the infrared view of this complex object. The blue-white region traces the cloud of energetic electrons trapped within the star's magnetic field, emitting so-called "synchrotron" radiation. The red features follow the well-known filamentary structures that permeate this nebula. Though they are known to contain hot gasses, their exact nature is still a mystery that astronomers are examining. The energetic cloud of electrons are driven by a rapidly rotating neutron star, or pulsar, at its core. The nebula is about 6,500 light-years away from the Earth, and is 5 light-years across. This false-color image presents images from Spitzer's Infrared Array Camera (IRAC) at 3.6 (blue), 4.5 (green), and 8.0 (red) microns. |
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Baby Stars Brewing in the Wi
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| Title |
Baby Stars Brewing in the Witch Head Nebula |
| Description |
Eight hundred light-years away in the Orion constellation, a gigantic murky cloud called the "Witch Head Nebula" is teeming with dust-obscured newborn stars waiting to be uncovered. In this image, the super sensitive infrared eyes of NASA's Spitzer Space Telescope reveals 12 new baby stars in a small portion of the cloud commonly referred to as the Witch Head's "pointy chin." Observations are currently underway to search for infant stars in the rest of the cloud. The image is a four-color composite where blue represents 3.6 microns, green depicts 4.5 microns, yellow is 5.8 microns, and red is 8.0 microns. |
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Double Helix Nebula
| Title |
Double Helix Nebula |
| Description |
The double helix nebula. The spots are infrared-luminous stars, mostly red giants and red supergiants. Many other stars are present in this region, but are too dim to appear even in this sensitive infrared image. The double helix nebula is approximately 300 light-years from the enormous black hole at the center of the Milky Way. (The Earth is more than 25,000 light-years from the black hole at the galactic center.) This false-color image was taken by the Multiband Imaging Photometer for Spitzer (MIPS). |
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Black Widow Nebula Hiding in
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| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Black Widow Nebula Hiding in
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| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Black Widow Nebula Hiding in
…
| Title |
Black Widow Nebula Hiding in the Dust |
| Description |
In the constellation Circinus, where previous visible-light observations by the Digital Sky Survey (left) saw only a faint hourglass-shaped patch of obscuring dust and gas, NASA's Spitzer Space Telescope's dust-piercing eyes see a big "Black Widow Nebula" teeming with clusters of massive young stars (right). In the Spitzer image, the two opposing bubbles are being formed in opposite directions by the powerful outflows from massive groups of forming stars. The baby stars can be seen as specks of yellow where the two bubbles overlap. When individual stars form from molecular clouds of gas and dust they produce intense radiation and very strong particle winds. Both the radiation and the stellar winds blow the dust outward from the star creating a cavity or, bubble. In the case of the Black Widow Nebula, astronomers suspect that a large cloud of gas and dust condensed to create multiple clusters of massive star formation. The combined winds from these groups of large stars probably blew out bubbles into the direction of least resistance, forming a double bubble. The infrared image was captured by the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a four-channel false-color composite, showing emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). |
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Baby Stars in the Witch Head
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| Title |
Baby Stars in the Witch Head Nebula |
| Description |
Eight hundred light-years away in the Orion constellation, a gigantic murky cloud called the "Witch Head" nebula is brewing baby stars. The stellar infants are revealed as pink dots in this image from NASA's Spitzer Space Telescope. Wisps of green in the cloud are carbon-rich molecules called polycyclic aromatic hydrocarbons, which are found on barbecue grills and in automobile exhaust on Earth. This image was obtained as part of the Spitzer Space Telescope Research Program for Teachers and Students, involving high school teachers and their students from across the United States. The infrared image is a three-color composite, in which light with a wavelength of 4.5 microns is blue, 8.0-micron light is green, and 24-micron light is red. |
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Comets Kick up Dust in Helix
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| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
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Comets Kick up Dust in Helix
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| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
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The Tarantula Nebula
| Title |
The Tarantula Nebula |
| Description |
NASA's new Spitzer Space Telescope has captured in stunning detail the spidery filaments and newborn stars of the Tarantula Nebula, a rich star-forming region also known as 30 Doradus. In this animation the infrared structures seen by this new observatory are compared with a visible light image from the ground-based European Southern Observatory (ESO) to highlight the power of Spitzer to see what other telescopes cannot. Starting with the ESO visible-light image, the spider-like filaments that inspired this nebula's name fill the view. The pinkish color in this image originates from the gas, mostly hydrogen heated to high temperatures by the many brilliant young stars. Dark swaths cutting through this region suggest the sooty, dense dust clouds that fuel star formation. Zooming into one dust lane at the upper right side of the nebula, the transition to the infrared view reveals a streamer of bright red emission from a visually dark cloud. Here, and throughout the nebula, these red filaments reveal the presence of molecular material thought to be rich in hydrocarbons, a Spitzer finding highlighting a previously unseen aspect of this nebula. Green indicate the hottest regions of gas, coming from the same hydrogen gas that produces the visible light. Moving down and around the heart of the Tarantula, the lower cavity of the nebula moves into view. Dense pillars of gas line the edge of this opening, looking almost like teeth around a mouth. In visible light the outer surfaces of these pillars glow brilliantly while the infrared view reveals a more complex structure. The green outer surfaces trace the surrounding hot gas while red filaments expose the dense, buried cloud cores, almost like a dentist's X-ray probing hidden roots within the teeth. Finally, pulling back to see the entire nebula, the striking differences and similarities between the visible and infrared images are clear. By expanding our view beyond the limits of visible light we can see otherwise invisible dust clouds and hidden stars that greatly enhance our understanding of the Tarantula Nebula. |
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Eagle Nebula Flaunts Its Inf
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| Title |
Eagle Nebula Flaunts Its Infrared Feathers |
| Description |
This set of images from NASA's Spitzer Space Telescope shows the Eagle nebula in different hues of infrared light. Each view tells a different tale. The left picture shows lots of stars and dusty structures with clarity. Dusty molecules found on Earth called polycyclic aromatic hydrocarbons produce most of the red, gas is green and stars are blue. The middle view is packed with drama, because it tells astronomers that a star in this region violently erupted, or went supernova, heating surrounding dust (orange). This view also reveals that the hot dust is shell shaped, another indication that a star exploded. The final picture highlights the contrast between the hot, supernova-heated dust (green) and the cooler dust making up the region's dusty star-forming clouds and towers (red, blue and purple). The left image is a composite of infrared light with the following wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8 microns (red). The right image includes longer infrared wavelengths, and is a composite of light of 4.5 to 8.0 microns (blue), 24 microns (green), and 70 microns (red). The middle image is made up solely of 24-micron light. |
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The Tarantula Nebula
| Title |
The Tarantula Nebula |
| Description |
NASA's new Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility, has captured in stunning detail the spidery filaments and newborn stars of the Tarantula Nebula, a rich star-forming region also known as 30 Doradus. This cloud of glowing dust and gas is located in the Large Magellanic Cloud, the nearest galaxy to our own Milky Way, and is visible primarily from the Southern Hemisphere. This image of an interstellar cauldron provides a snapshot of the complex physical processes and chemistry that govern the birth -- and death -- of stars. At the heart of the nebula is a compact cluster of stars, known as R136, which contains very massive and young stars. The brightest of these blue supergiant stars are up to 100 times more massive than the Sun, and are at least 100,000 times more luminous. These stars will live fast and die young, at least by astronomical standards, exhausting their nuclear fuel in a few million years. The Spitzer Space Telescope image was obtained with an infrared array camera that is sensitive to invisible infrared light at wavelengths that are about ten times longer than visible light. In this four-color composite, emission at 3.6 microns is depicted in blue, 4.5 microns in green, 5.8 microns in orange, and 8.0 microns in red. The image covers a region that is three-quarters the size of the full moon. The Spitzer observations penetrate the dust clouds throughout the Tarantula to reveal previously hidden sites of star formation. Within the luminescent nebula, many holes are also apparent. These voids are produced by highly energetic winds originating from the massive stars in the central star cluster. The structures at the edges of these voids are particularly interesting. Dense pillars of gas and dust, sculpted by the stellar radiation, denote the birthplace of future generations of stars. The Spitzer image provides information about the composition of the material at the edges of the voids. The surface layers closest to the massive stars are subject to the most intense stellar radiation. Here, the atoms are stripped of their electrons, and the green color of these regions is indicative of the radiation from this highly excited, or 'ionized,' material. The ubiquitous red filaments seen throughout the image reveal the presence of molecular material thought to be rich in hydrocarbons. The Tarantula Nebula is the nearest example of a 'starburst' phenomenon, in which intense episodes of star formation occur on massive scales. Most starbursts, however, are associated with dusty and distant galaxies. Spitzer infrared observations of the Tarantula provide astronomers with an unprecedented view of the lifecycle of massive stars and their vital role in regulating the birth of future stellar and planetary systems. |
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NGC 1999: Reflection Nebula
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| Title |
NGC 1999: Reflection Nebula in Orion |
| Explanation |
A dusty bright nebula [ http://home.wxs.nl/~geldo006/brigneb.html ] contrasts dramatically with a dusty dark nebula in this Hubble Space Telescope image [ http://oposite.stsci.edu/pubinfo/pr/2000/10/index.html ] recorded shortly after December's orbital servicing mission [ http://hubble.gsfc.nasa.gov/ ]. The nebula [ http://oposite.stsci.edu/pubinfo/pr/2000/10/faq.html ], cataloged as NGC [ http://antwrp.gsfc.nasa.gov/apod/ap990429.html ] 1999, is a reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ], which shines by reflecting light from a nearby star. Unlike emission nebulae [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], whose reddish glow [ http://antwrp.gsfc.nasa.gov/apod/ap980828.html ] comes from excited atoms of gas, reflection nebulae have a bluish cast [ http://www.physics.muni.cz/~ondra/mix/mix.html ] as their interstellar dust grains [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] preferentially reflect blue starlight. While perhaps the most famous reflection nebulae surround the bright young stars of the Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap000227.html ] star cluster, NGC 1999's stellar illumination is provided by the embedded variable star V380 [ http://donald.phast.umass.edu/research/comap/V380sm.html ] Orionis, seen here just left of center. Extending right of center, the ominous [ http://antwrp.gsfc.nasa.gov/apod/ap990226.html ] dark nebula [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ] is actually a condensation of cold molecular gas and dust so thick and dense that it blocks light. From our perspective it lies in front of the bright nebula, silhouetted against the ghostly nebular glow. New stars [ http://dsnra.jpl.nasa.gov/origins/nyt.html ] will likely form within the dark cloud, called a Bok globule [ http://antwrp.gsfc.nasa.gov/apod/ap961229.html ], as self-gravity continues to compress its dense gas and dust. Reflection nebula NGC 1999 [ http://heritage.stsci.edu/public/ 2000mar2/ngc1999table.html ] lies about 1500 light-years away in the constellation Orion [ http://www.seds.org/messier/more/oricloud.html ], just south of Orion's well known emission nebula, M42 [ http://antwrp.gsfc.nasa.gov/apod/ap990522.html ]. |
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Comet Meets Ring Nebula: Par
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| Title |
Comet Meets Ring Nebula: Part I |
| Explanation |
As dawn approached on May 8, astronomer Stefan Seip carefully watched Fragment C of broken [ http://neo.jpl.nasa.gov/cgi-bin/db?name=73P ] comet 73P/Schwassmann-Wachmann 3 [ http://skyandtelescope.com/observing/objects/comets/ article_1704_1.asp ] approach M57 [ http://seds.lpl.arizona.edu/messier/m/m057.html ] - the Ring Nebula, and faint spiral galaxy IC 1296 [ http://www.skyhound.com/sh/archive/jul/IC_1296.html ]. Of course, even though the trio seemed to come close together in a truly cosmic photo opportunity, the comet [ http://antwrp.gsfc.nasa.gov/apod/ap060504.html ] is in the inner part of our solar system, a mere 0.5 light-minutes [ http://en.wikipedia.org/wiki/Light-minute ] or so from Seip's telescope located near Stuttgart, Germany, planet Earth [ http://science.nasa.gov/headlines/y2006/ 24mar_73p.htm?list237669 ]. The Ring Nebula (upper right) is more like 2,000 light-years distant, well within our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap050825.html ]. At a distance of 200 million light-years, IC 1296 (between comet and ring) is beyond even the Milky Way's boundaries. Because the comet is so close, it appears to move relatively rapidly against the distant stars. This dramatic telescopic view [ http://www.photomeeting.de/astromeeting/comets/ 060508SchwWas_a_d.htm ] was composited from two sets of images, one compensating [ http://www.ewellobservatory.com/ccd/ comet.cfm ] for the comet's apparent motion and one recording the background stars and nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap030516.html ]. |
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MyCn18: An Hourglass Nebula
| Title |
MyCn18: An Hourglass Nebula |
| Explanation |
The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.pppl.gov/CPEP/ Chart_Pages/5.Plasmas/Nebula/Planetary.html ]. With its nuclear fuel [ http://fusedweb.pppl.gov/default.html ] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://observe.ivv.nasa.gov/nasa/space/stellardeath/stellardeath_contents.html ] occurs as its outer layers are ejected - its core becoming a cooling, fading White Dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap971102.html ]. Astronomers have recently used the Hubble Space Telescope [ http://hubble.stsci.edu/ ] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ], including the one above [ http://www.stsci.edu/pubinfo/PR/96/07.html ]. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.edu/pubinfo/gif/Hourgls.txt ] of the nebula ejection process [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://www.astro.washington.edu/balick/WFPC2/index.html ]. |
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IC 418: The Spirograph Nebul
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| Title |
IC 418: The Spirograph Nebula |
| Explanation |
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] for its resemblance to drawings from a cyclical drawing tool [ http://www.wordsmith.org/~anu/java/spirograph.html ], planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] IC 418 shows patterns [ http://mathworld.wolfram.com/Spirograph.html ] that are not well understood. Perhaps they are related to chaotic winds [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] from the variable central star, which changes brightness unpredictably [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...320..125H ] in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 [ http://www.skyhound.com/sh/archive/jan/IC_418.html ] was probably a well-understood star similar to our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. Only a few thousand years ago, IC 418 was probably a common red giant [ http://www.historyoftheuniverse.com/starold.html ] star. Since running out of nuclear fuel [ http://csep10.phys.utk.edu/astr162/lect/energy/ppchain.html ], though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], visible in the image [ http://heritage.stsci.edu/public/2000sept7/displayic418.html ] center. The light from the central core excites surrounding atoms [ http://www.pbs.org/wgbh/aso/tryit/atom/ ] in the nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] causing them to glow. IC 418 lies about 2000 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away and spans 0.3 light-years across. This recently released false-color image [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] taken from the Hubble Space Telescope [ http://www.stsci.edu/hst/ ] reveals the unusual details. |
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The Eagle Nebula in Infrared
| Title |
The Eagle Nebula in Infrared |
| Explanation |
In visible light, the whole thing looks like an eagle [ http://video.google.com/videoplay?docid=-4639730101975502715&q=eagle&hl=en ]. The region was captured recently in unprecedented detail in infrared light [ http://imagers.gsfc.nasa.gov/ems/infrared.html ] by the robotic orbiting Spitzer Space Telescope [ http://en.wikipedia.org/wiki/Spitzer_space_telescope ] (SSC). Shown above [ http://www.spitzer.caltech.edu/Media/releases/ssc2007-01/ssc2007-01a.shtml ], the infrared image allows observers to peer through normally opaque dust [ http://antwrp.gsfc.nasa.gov/apod/ap060409.html ] and so better capture the full complexity of the Eagle Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060226.html ] star forming region. In particular, the three famous pillars [ http://antwrp.gsfc.nasa.gov/apod/ap050424.html ] near the image center are seen bathed in dust likely warmed by a supernova [ http://en.wikipedia.org/wiki/Supernova ] explosion. The warm dust is digitally assigned the false color of red. Also visible, near the bottom of the image, is ten light-year long pillar sometimes dubbed the Fairy [ http://antwrp.gsfc.nasa.gov/apod/ap050425.html ] of Eagle Nebula. The greater Eagle emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ], tagged M16, lies about 6500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away, spans about 20 light-years, and is visible with binoculars [ http://www.birdwatching.com/optics/binoculars1.html#How Binoculars Work ] toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Serpens [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=76 ]. |
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Dust and the Helix Nebula
| Title |
Dust and the Helix Nebula |
| Explanation |
Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image [ http://www.spitzer.caltech.edu/Media/releases/ ssc2007-03/index.shtml ] shows infrared [ http://coolcosmos.ipac.caltech.edu// ] radiation from the well-studied Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060112.html ] (NGC 7293) a mere 700 light-years away in the constellation Aquarius [ http://www.seds.org/Maps/Stars_en/Fig/aquarius.html ]. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ], representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models [ http://arxiv.org/abs/astro-ph/0702296 ] suggest the glow is produced by a dust debris disk [ http://antwrp.gsfc.nasa.gov/apod/ap041210.html ]. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt [ http://www.ifa.hawaii.edu/faculty/jewitt/kb/kb.con.html ] or cometary Oort cloud [ http://www.windows.ucar.edu/tour/ link=/comets/Oort_cloud.html&edu=high ]. Formed in the distant planetary system, the comet-like bodies have otherwise survived even the dramatic late stages of the star's evolution [ http://en.wikipedia.org/wiki/Stellar_evolution ]. |
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The Witch Head Nebula
| Title |
The Witch Head Nebula |
| Explanation |
Double, double toil and trouble, Fire burn, and cauldron bubble -- maybe Macbeth [ http://tech-two.mit.edu/Shakespeare/macbeth/index.html ] should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula [ http://antwrp.gsfc.nasa.gov/apod/reflection_nebulae.html ] is associated with the bright star Rigel [ http://www.astro.uiuc.edu/~kaler/sow/rigel.html ] in the constellation Orion [ http://www.astro.uiuc.edu/~kaler/sow/orion-p.html ]. More formally known as IC 2118 [ http://www.astrocruise.com/ic2118.htm ], the Witch Head Nebula glows primarily by light reflected from Rigel [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997MNRAS.290..521I ], located just outside the top right corner of the above image [ http://home.earthlink.net/~gstevens914/pwitch.htm ]. Fine dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light [ http://www.physics.muni.cz/~ondra/mix/mix.html ] more efficiently than red. The same physical process [ http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html ] causes Earth's daytime sky to appear blue [ http://math.ucr.edu/home/baez/physics/blue_sky.html ], although the scatterers in Earth's atmosphere [ http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html ] are molecules of nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ] and oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ]. The nebula lies about 1000 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away. |
|
Planetary Nebula Mz3: The An
…
| Title |
Planetary Nebula Mz3: The Ant Nebula |
| Explanation |
Why isn't this ant a big sphere? Planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] Mz3 is being cast off by a star similar to our Sun [ http://www.nineplanets.org/sol.html ] that is, surely, round. Why then would the gas that is streaming away create an ant [ http://www.discovery.com/cams/ant/learn.html ]-shaped nebula that is distinctly not round? Clues might include [ http://hubble.esa.int/hubble/news/ index.cfm?oid=25994 ] the high 1000-kilometer per second speed of the expelled gas, the light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/ questions/question19.html ] long length of the structure, and the magnetism [ http://www.wondermagnet.com/dev/magfaq.html ] of the star visible above [ http://heritage.stsci.edu/public/2001feb/display.html ] at the nebula's center. One possible answer is that Mz3 [ http://heritage.stsci.edu/public/2001feb/table.html ] is hiding a second, dimmer star that orbits close [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ] in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field [ http://antwrp.gsfc.nasa.gov/apod/ap980629.html ] are channeling the gas. Since the central star appears to be so similar to our own Sun, astronomers [ http://www.aas.org/%7Eeducation/career.html ] hope that increased understanding of the history of this giant space ant [ http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2064.html ] can provide useful insight into the likely future of our own Sun [ http://antwrp.gsfc.nasa.gov/apod/sun.html ] and Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ]. |
|
The Snowflake Cluster versus
…
| Title |
The Snowflake Cluster versus the Cone Nebula |
| Explanation |
Strange shapes and textures can be found in the neighborhood of the Cone Nebula. These patterns result from the tumultuous unrest that accompanies the formation of the open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] of stars known as NGC 2264 [ http://www.seds.org/messier/xtra/ngc/n2264.html ], the Snowflake cluster. To better understand this process, a detailed image of this region was taken in two colors of infrared light [ http://coolcosmos.ipac.caltech.edu//cosmic_classroom/classroom_activities/herschel_bio.html ] by the orbiting Spitzer Space Telescope [ http://en.wikipedia.org/wiki/Spitzer_Space_Telescope ]. Bright stars from the Snowflake [ http://www.its.caltech.edu/~atomic/snowcrystals/photos/photos.htm ] cluster dot the field. These stars soon heat up and destroy the gas and dust mountains [ http://antwrp.gsfc.nasa.gov/apod/ap051111.html ] in which they formed. One such dust mountain [ http://antwrp.gsfc.nasa.gov/apod/ap070224.html ] is the famous Cone Nebula, visible in the above image [ http://sscws1.ipac.caltech.edu/Imagegallery/image.php?image_name=sig05-028 ] on the left, pointing toward a bright star near the center of the field. The entire NGC 2264 [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?2264 ] region is located about 2,500 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation of the Unicorn [ http://en.wikipedia.org/wiki/Unicorn ] (Monoceros [ http://www.astronomical.org/portal/modules/wfsection/article.php?articleid=55 ]). |
|
Hot Stars in the Rosette Neb
…
| Title |
Hot Stars in the Rosette Nebula |
| Explanation |
Winds and radiation from massive hot stars in the Rosette Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap070214.html ] have cleared the natal gas and dust [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ cosmic_reference/dust.html ] from the center of the nearby star-forming region. They also pose a danger to planet forming disks [ http://antwrp.gsfc.nasa.gov/apod/ap041210.html ] around young, cooler stars in the neighborhood. This Spitzer Space Telescope infrared image [ http://gallery.spitzer.caltech.edu/ Imagegallery/image.php?image_name=ssc2007-08b ] of dust clouds near the Rosette's central region, shows the cleared-out cavity. The view spans about 45 light-years at the the nebula's estimated distance of 5,200 light-years. Putting your cursor over the false color picture will highlight the dangerous hot stars, classified as O stars [ http://www.astro.uiuc.edu/~kaler/sow/ spectra.html#classes ] with surface temperatures of 25,000 kelvins [ http://en.wikipedia.org/wiki/Kelvin ] or higher. Astronomers calculate [ http://arxiv.org/abs/astro-ph/0701741 ] that cool stars wandering within about 1.6 light-years of the Rosette's O stars are in danger of having their planet forming disks destroyed [ http://antwrp.gsfc.nasa.gov/apod/ap010504.html ]. |
|
Halloween and the Ghost Head
…
| Title |
Halloween and the Ghost Head Nebula |
| Explanation |
Halloween's origin [ http://www.historychannel.com/exhibits/halloween/holiday_origins1.html ] is ancient and astronomical. Since the fifth century BC, Halloween [ http://en.wikipedia.org/wiki/Halloween ] has been celebrated as a cross-quarter day [ http://www-astronomy.mps.ohio-state.edu/~pogge/Ast161/Unit2/time.html ], a day halfway between an equinox [ http://antwrp.gsfc.nasa.gov/apod/ap000923.html ] (equal day / equal night) and a solstice [ http://antwrp.gsfc.nasa.gov/apod/ap971221.html ] (minimum day / maximum night in the northern hemisphere). With our modern calendar [ http://webexhibits.org/calendars/year-countries.html ], however, the real cross-quarter day [ http://www.whyy.org/tv12/franklinfacts/oct3100ff.html ] will occur next week. Another cross-quarter day is Groundhog's Day [ http://www.noblenet.org/year/groundhog.htm ]. Halloween's [ http://www.census.gov/Press-Release/www/releases/archives/facts_for_features_special_editions/010511.html ] modern celebration retains historic roots [ http://www.neopagan.net/Halloween-Origins.html ] in dressing to scare away the spirits of the dead. Perhaps a fitting modern tribute to this ancient holiday is the above-pictured Ghost Head Nebula [ http://photojournal.jpl.nasa.gov/catalog/PIA04226 ] taken with the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ]. Appearing similar to the icon of a fictional [ http://en.wikipedia.org/wiki/Casper_the_Friendly_Ghost ] ghost [ http://en.wikipedia.org/wiki/Ghost ], NGC 2080 is actually a star forming region [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ] in the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010804.html ], a satellite galaxy of our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ]. The Ghost Head Nebula spans about 50 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] and is shown in representative colors. |
|
Halloween and the Ghost Head
…
| Title |
Halloween and the Ghost Head Nebula |
| Explanation |
Halloween's origin [ http://teacherlink.ed.usu.edu/TLresources/longterm/LessonPlans/Byrnes/halloween.html ] is ancient and astronomical. Since the fifth century BC, Halloween [ http://www.historychannel.com/exhibits/halloween/ ] has been celebrated as a cross-quarter day [ http://www-astronomy.mps.ohio-state.edu/~pogge/Ast161/Unit2/time.html ], a day halfway between an equinox [ http://antwrp.gsfc.nasa.gov/apod/ap000923.html ] (equal day / equal night) and a solstice [ http://antwrp.gsfc.nasa.gov/apod/ap971221.html ] (minimum day / maximum night in the northern hemisphere). With our modern calendar [ http://webexhibits.org/calendars/year-countries.html ], however, the real cross-quarter day [ http://www.whyy.org/tv12/franklinfacts/oct3100ff.html ] will occur next week. Another cross-quarter day is Groundhog's Day [ http://www.hansenplanetarium.net/CQGroundhog.html ]. Halloween's [ http://www.jpl.nasa.gov/proto/ halloween_sounds.html ] modern celebration retains historic roots [ http://www.utah.edu/planetarium/CQHalloween.html ] in dressing to scare away the spirits of the dead. A perhaps-fitting modern tribute to this ancient holiday is the above-pictured Ghost Head Nebula [ http://hubble.esa.int/hubble/news/image.cfm?oid=28749&ooid=28750 ] taken with the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ]. Appearing similar to the icon of a fictional ghost [ http://www.yesterdayland.com/popopedia/shows/saturday/sa1025.php ], NGC 2080 is actually a star forming region [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ] in the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010804.html ], a satellite galaxy of our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ]. The Ghost Head Nebula spans about 50 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] and is shown in representative colors. |
|
The Snake Nebula from CFHT
| Title |
The Snake Nebula from CFHT |
| Explanation |
What slithers overhead? The dark winding lanes visible in part of the constellation [ http://www.adlerplanetarium.org/history/exhibits/constellations/timeline.html ] of Ophiuchus [ http://www.seds.org/Maps/Stars_en/Fig/ophiuchus.html ] belong to the Snake Nebula [ http://www.darkskyimages.com/snake.htm ]. Also known as Barnard [ http://astro.uchicago.edu/yerkes/virtualmuseum/Barnard.html ] 72, the Snake Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970824.html ] is a series of dark absorption clouds [ http://antwrp.gsfc.nasa.gov/apod/dark_nebulae.html ] made up of molecular gas [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] and interstellar dust. Interstellar dust grains [ http://antwrp.gsfc.nasa.gov/apod/ap010813.html ] - composed predominantly of carbon [ http://pearl1.lanl.gov/periodic/elements/6.html ] - absorb visible starlight and reradiate much of it in the infrared [ http://www.gemini.edu/public/infrared.html ]. This absorption causes stars behind the clouds [ http://www.anzwers.org/free/universe/darknebs.html ] to be obscured from view, hence the appearance of starless voids [ http://antwrp.gsfc.nasa.gov/apod/ap010923.html ] on the sky. Molecular clouds [ http://origins.jpl.nasa.gov/poster/bigbang3.html ] like the Snake Nebula [ http://www.rawbw.com/~shekhar/b72.html ] are places where new stars [ http://antwrp.gsfc.nasa.gov/apod/ap011125.html ] are likely to form. The Snake Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1977ApJ...213..654R ], pictured above [ http://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/CFHT-Coelum-AIOM-Apr2002.html ], lies about 650 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away and spans the angular width of a full moon [ http://antwrp.gsfc.nasa.gov/apod/ap010218.html ]. |
|
MyCn18: An Hourglass Nebula
| Title |
MyCn18: An Hourglass Nebula |
| Explanation |
The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.pppl.gov/CPEP/ Chart_Pages/5.Plasmas/Nebula/Planetary.html ]. With its nuclear fuel [ http://fusedweb.pppl.gov/default.html ] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://www.astro.virginia.edu/class/hawley/astr124/starbirth.html ] occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap000910.html ]. In 1995, astronomers used the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ], including the one above [ http://www.stsci.edu/pubinfo/PR/96/07.html ]. Here, delicate rings of colorful glowing gas (nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ]-red, hydrogen [ http://pearl1.lanl.gov/periodic/elements/1.html ]-green, and oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ]-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.edu/pubinfo/gif/Hourgls.txt ] of the nebula ejection process [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://www.astro.washington.edu/balick/WFPC2/index.html ]. |
|
MyCn18: An Hourglass Nebula
| Title |
MyCn18: An Hourglass Nebula |
| Explanation |
The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.pppl.gov/CPEP/ Chart_Pages/5.Plasmas/Nebula/Planetary.html ]. With its nuclear fuel [ http://fusedweb.pppl.gov/default.html ] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://plabpc.csustan.edu/astro/stars/stars.htm ] occurs as its outer layers are ejected - its core becoming a cooling, fading White Dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap950910.html ]. Astronomers have recently used the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap950729.html ], including the one above [ http://www.stsci.edu/pubinfo/PR/96/07.html ]. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.edu/pubinfo/gif/Hourgls.txt ] of the nebula ejection process [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/lib/planetary.html ]. |
|
Henize 3-401: An Elongated P
…
| Title |
Henize 3-401: An Elongated Planetary Nebula |
| Explanation |
How do dying stars eject their outer layers? Stars that create elegant planetary nebulas [ http://www.noao.edu/jacoby/pn_gallery.html ] like Henize 3-401, pictured above [ http://hubble.esa.int/hubble/news/image.cfm?oid=30272&ooid=30277 ], are not unusual, causing speculation that, one day, our own Sun [ http://www.nineplanets.org/sol.html ] may look like this. Henize 3-401 is one of the most elongated planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/ap020106.html ]s yet discovered, a particularly odd feat [ http://antwrp.gsfc.nasa.gov/apod/ap020618.html ] for a seemingly round star. Perhaps, some astronomers hypothesize, the elongated shape gives a clue to the expulsion mechanism. Genesis hypotheses include that the outer layers of gas are funneled out by the star's own magnetic field [ http://www-istp.gsfc.nasa.gov/Education/Imagnet.html ], and that a second unseen star is somehow involved. After the gas disperses in a few thousand years, only a white dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ] will remain. Henize 3-401 lies about 10,000 light years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away toward the constellation [ http://www.emufarm.org/~cmbell/myth/myth.html ] of Carina [ http://www.astronomical.org/constellations/car.html ]. |
|
The Eye of an Hourglass Nebu
…
| Title |
The Eye of an Hourglass Nebula |
| Explanation |
What's happening in the eye-like center of this planetary nebula? [ http://www.noao.edu/jacoby/pn_gallery.html ] The geometry revealed in this Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap960128.html ] view of the central part of an "etched hourglass nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960118.html ]" known as MyCn 18 [ http://www.stsci.edu/pubinfo/gif/Hourgls.txt ] presents a puzzle. First, the axis of this central region does not line up well with the outer hourglass structure. Next, the hot star (the white spot to the left of center) which ejected this gaseous nebula as it evolved towards its white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap950910.html ] phase, is not exactly at the center of the "eye". These unexpected results leave astronomers looking for the missing pieces of the ejection process that created this unusual and beautiful structure. |
|
Searchlight Beams from the E
…
| Title |
Searchlight Beams from the Egg Nebula |
| Explanation |
The dramatic and mysterious looking object revealed in this Hubble Space Telescope image [ http://www.stsci.edu/pubinfo/gif/EggNeb.txt ] is known as the Egg Nebula [ http://www.stsci.edu/pubinfo/PR/96/03.html ]. It is an aging star about 3,000 lightyears distant, entering its Planetary Nebula [ http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/ Nebula/Planetary.html ] phase of evolution. Surrounded by an expanding cloud of gas and dust, a dense cocoon of dust (seen as the dark band running diagonally across the center) encloses the star itself and blocks it from direct view. The searchlight appearance is created as light from the star shines more easily through the thinner parts of the cocoon. Dust particles in the expanding cloud scatter and reflect the starlight making the beams visible. The sharpness of the HST image reveals a wealth of detail which will help to understand this complex and spectacular part of the stellar lifecycle [ http://antwrp.gsfc.nasa.gov/apod/ap960118.html ]. |
|
Cold Wind from the Boomerang
…
| Title |
Cold Wind from the Boomerang Nebula |
| Explanation |
A cold wind blows from the central star of the Boomerang Nebula. Seen here in a detailed false-color image recorded in 1998 by the Hubble Space Telescope [ http://hubble.esa.int/hubble/news/ index.cfm?oid=31442 ], the nebula lies about 5,000 light-years away towards the grand southern constellation of Centaurus [ http://www.astro.wisc.edu/~dolan/constellations/extra/ Centaurus.html ]. The symmetric cloud appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of nearly 600,000 kilometers per hour. This rapid expansion has cooled molecules in the nebular gas to about one degree above absolute zero [ http://www.unidata.ucar.edu/staff/blynds/tmp.html ] - colder than even the cosmic background radiation [ http://www.ncsa.uiuc.edu/Cyberia/Cosmos/Footprints.html ] - making it the coldest region observed in the distant Universe [ http://antwrp.gsfc.nasa.gov/apod/ap030212.html ]. Shining with light from the central star reflected by dust, the frigid Boomerang Nebula is believed to be [ http://adsabs.harvard.edu/cgi-bin/ nph-bib_query?1997ApJ%2E%2E%2E487L%2E155S&db_key=AST ] a star or stellar system evolving toward [ http://antwrp.gsfc.nasa.gov/apod/ap020807.html ] the planetary nebula phase [ http://antwrp.gsfc.nasa.gov/apod/ap020615.html ]. |
|
A Close-Up of the Lagoon Neb
…
| Title |
A Close-Up of the Lagoon Nebula |
| Explanation |
Ribbons of red-glowing gas [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] and dark dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] surround massive young stars in this close-up of the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960127.html ] taken by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ]. The Lagoon Nebula [ http://seds.lpl.arizona.edu/billa/twn/n6523x.html ] is relatively close and bright - it appears larger than the Full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap960730.html ] and is visible even without a telescope [ http://aci.mta.ca/TheUmbrella/Physics/Astronomy/Telescope.html ]. Light takes about 5000 years to reach here from there. The Lagoon Nebula [ http://seds.lpl.arizona.edu/messier/m/m008.html ] houses the open star cluster [ http://antwrp.gsfc.nasa.gov/apod/lib/open_clusters.html ] M [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]8. This photograph [ http://scivax.stsci.edu/~hamilton/nuggets/HST_NUGGETS.HTML ] is combination of exposures taken in the red, green and ultraviolet. The unusual bright central part of the Lagoon Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-article_query?bibcode=1990ApJ%2E%2E%2E357%2E%2E502M&page=1&plate_select=NO&type=GIF ] (lower left in this image) is known as the Hourglass Nebula. |
|
The Egg Nebula in Polarized
…
| Title |
The Egg Nebula in Polarized Light |
| Explanation |
Where is the center of the unusual Egg Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960129.html ]? Like a baby chick [ http://www.msichicago.org/exhibit/chick/chick.html ] pecking its way out of an egg, the star in the center of the Egg Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap990626.html ] is casting away shells of gas and dust as it slowly transforms itself into a white dwarf [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ] star. The Egg Nebula [ http://heritage.stsci.edu/2003/09/caption.html ] is a rapidly evolving pre [ http://www.noao.edu/noao/noaonews/sep98/node3.html ]-planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] spanning about one light year [ http://www.howstuffworks.com/question94.htm ] toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Cygnus [ http://www.astronomical.org/constellations/cyg.html ]. Thick dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ], though, blocks the center star from view, while the dust shells further out reflect light from this star. Light vibrating [ http://www.colorado.edu/physics/2000/waves_particles/wavpart4.html ] in the plane defined [ http://www.math.hmc.edu/calculus/tutorials/linesplanesvectors/ ] by each dust grain, the central star, and the observer is preferentially reflected [ http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polar.html ], causing an effect known as polarization [ http://www.colorado.edu/physics/2000/polarization/polarizationI.html ]. Measuring the orientation of the polarized light [ http://www.polarization.com/ ] for the Egg Nebula [ http://oposite.stsci.edu/pubinfo/pr/2003/09/weintraub2000_v531.pdf ] gives clues to location of the hidden source. The above image [ http://heritage.stsci.edu/2003/09/big.html ] taken by the Advanced Camera for Surveys [ http://acs.pha.jhu.edu/ ] on the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ] is false-color coded to highlight [ http://heritage.stsci.edu/2003/09/supplemental.html ] the orientation of polarization. |
|
The Bubble Nebula from NOAO
| Title |
The Bubble Nebula from NOAO |
| Explanation |
It's the bubble versus the cloud. NGC 7635, the Bubble Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap030117.html ], is being pushed out by the stellar wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] of massive central star BD+602522. Next door, though, lives a giant molecular cloud [ http://antwrp.gsfc.nasa.gov/apod/ap030202.html ], visible above to the lower right. At this place in space, an irresistible force meets an immovable object in an interesting way. The cloud [ http://heritage.stsci.edu/1998/31/index.html ] is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the bubble [ http://www.exploratorium.edu/ronh/bubbles/bubbles.html ]'s central star. The radiation [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ] heats up dense regions of the molecular cloud [ http://origins.jpl.nasa.gov/poster/bigbang3.html ] causing it to glow. The Bubble Nebula, pictured above [ http://www.noao.edu/outreach/aop/observers/n7635.html ] as a color negative to help bring up contrast, is about 10 light-years across and part of a much larger complex of stars and shells. The Bubble Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000118.html ] can be seen with a small telescope towards the constellation of Cassiopeia [ http://www.astronomical.org/constellations/cas.html ]. |
|
The Tarantula Nebula from Sp
…
| Title |
The Tarantula Nebula from Spitzer |
| Explanation |
In the heart of monstrous Tarantula Nebula [ http://www.seds.org/messier/xtra/ngc/n2070.html ] lies one of the most unusual star clusters [ http://antwrp.gsfc.nasa.gov/apod/ap010730.html ]. Known as NGC 2070 or R136 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...493..180M ], it is home to a great number of hot young stars [ http://antwrp.gsfc.nasa.gov/apod/ap031227.html ]. The energetic light from these stars continually ionizes [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] nebula gas, while their energetic particle wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] blows bubbles [ http://antwrp.gsfc.nasa.gov/apod/ap030617.html ] and defines intricate filaments [ http://antwrp.gsfc.nasa.gov/apod/ap030118.html ]. The new Spitzer Space Telescope [ http://www.spitzer.caltech.edu/about/index.shtml ] took the above representative-color [ http://www.spitzer.caltech.edu/Media/releases/ssc2004-01/ssc2004-01a.shtml ] infrared image [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html ] of this great LMC [ http://antwrp.gsfc.nasa.gov/apod/ap010804.html ] cluster. The image details the cluster's tumultuous center in gas, dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] and young stars. The 30 Doradus [ http://antwrp.gsfc.nasa.gov/apod/ap030622.html ] nebula is one of the largest star-formation regions known, and has been creating unusually strong episodes of star formation [ http://archive.ncsa.uiuc.edu/Cyberia/Bima/StarForm.html ] every few million years. In the heart of this heart is a central knot of stars [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1984AExpr...1...45W ] that is so dense [ http://antwrp.gsfc.nasa.gov/apod/ap991027.html ] it was once thought to be a single star. |
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MyCn18: An Hourglass Nebula
| Title |
MyCn18: An Hourglass Nebula |
| Explanation |
The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.pppl.gov/CPEP/ Chart_Pages/5.Plasmas/Nebula/Planetary.html ]. With its nuclear fuel [ http://fusedweb.pppl.gov/default.html ] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://plabpc.csustan.edu/astro/stars/stars.htm ] occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap950910.html ]. Astronomers have recently used the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap950729.html ], including the one above [ http://www.stsci.edu/pubinfo/PR/96/07.html ]. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.edu/pubinfo/gif/Hourgls.txt ] of the nebula ejection process [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/lib/planetary.html ]. |
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Cold Wind From The Boomerang
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| Title |
Cold Wind From The Boomerang Nebula |
| Explanation |
A cold wind blows from the central star of the Boomerang Nebula. Seen here in a false color image [ http://www2.jpl.nasa.gov/files/images/captions/p48793.txt ] of dust reflected starlight, the nebula lies about 5,000 light-years away. The boomerang shaped cloud appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of over 300,000 miles per hour. This rapid expansion has cooled the nebular gas to about -458 degrees Fahrenheit or 1 degree above absolute zero [ http://www.unidata.ucar.edu/staff/blynds/tmp.html ], making it the coldest region [ http://www.jpl.nasa.gov/releases/coldspot.html ] observed in the distant Universe [ http://www.ncsa.uiuc.edu/Cyberia/Cosmos/Footprints.html ]. The frigid Boomerang nebula represents a unique object for astronomers and is believed to be [ http://adsabs.harvard.edu/cgi-bin/ nph-bib_query?1997ApJ%2E%2E%2E487L%2E155S&db_key=AST ] a star or stellar system evolving toward the planetary nebula phase [ http://antwrp.gsfc.nasa.gov/apod/ap970914.html ]. |
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Hale-Bopp and the North Amer
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| Title |
Hale-Bopp and the North American Nebula |
| Explanation |
Comet Hale-Bopp [ http://galileo.ivv.nasa.gov/comet/ ]'s recent encounter with the inner Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap961214.html ] allowed many breath-taking pictures. Above, Comet Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] was photographed on March 8th in the constellation of Cygnus [ http://astro.gmu.edu/constellation/CYG.html ]. Visible on the right in red is the North American Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960606.html ], a bright emission nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#emis_neb ] observable from a dark location with binoculars. The North American Nebula [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989A%26A%2E%2E%2E222%2E%2E%2E82S&db_key=AST&nosetcookie=1 ] is about 1500 light years away, much farther than the comet, which was about 8 light minutes away. Several bright blue stars from the open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap970128.html ] M39 are visible just above the comet's blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap960502.html ]. |
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Planetary Nebula NGC 7027 in
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| Title |
Planetary Nebula NGC 7027 in Infrared |
| Explanation |
NGC 7027 [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ] is one of the smallest known planetary nebulae [ http://www.seds.org/messier/planetar.html ]. Even so, NGC 7027 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997A%26A%2E%2E%2E323%2E%2E217P&db_key=AST&high=33613e8e5825712&nosetcookie=1 ] is 14,000 times larger than the Earth-Sun distance [ http://encarta.msn.com/index/concise/0VOL0E/01b40000.asp ]. Planetary nebula are so named [ http://antwrp.gsfc.nasa.gov/apod/ap980218.html ] because the first few discovered appeared similar to planets. Planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/ap971223.html ] are actually dying stars, though, that have recently run out of nuclear fuel. The outer gaseous shells are expelled by an unknown process, frequently creating spectacular displays [ http://antwrp.gsfc.nasa.gov/apod/ap961203.html ]. In the above picture [ http://oposite.stsci.edu/pubinfo/pr/1998/11/a.html ] in infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/discovery.html ], the hot central star is visible. Our Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960916.html ] will become a planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970802.html ] in about 5 billion years. |
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Comet Hale-Bopp and the Nort
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| Title |
Comet Hale-Bopp and the North America Nebula |
| Explanation |
Comet Hale-Bopp [ http://www2.jpl.nasa.gov/comet/ ]'s 1997 encounter with the inner Solar System [ http://www.nineplanets.org/overview.html ] allowed many breath-taking pictures [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?hale+bopp ]. Above [ http://www.skylook.net/album/comet/habo/hab3i.htm ], Comet Hale-Bopp was photographed crossing the constellation of Cygnus, sporting spectacular yellow dust and blue ion tails [ http://www.ifa.hawaii.edu/faculty/jewitt/tail.html ]. Visible on the right in red is the North America Nebula [ http://www.seds.org/messier/xtra/ngc/n7000.html ], a bright emission nebula [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] observable from a dark location with binoculars. The North America Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000501.html ] is about 1500 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] away, much farther than the comet, which was only about 8 light minutes away. Several bright blue stars from the open cluster [ http://seds.lpl.arizona.edu/messier/open.html ] M39 [ http://antwrp.gsfc.nasa.gov/apod/ap040331.html ] are visible just above the comet's blue ion tail [ http://pwg.gsfc.nasa.gov/istp/events/halebopp/disconnect/ ]. |
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IC 418: The Spirograph Nebul
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| Title |
IC 418: The Spirograph Nebula |
| Explanation |
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] for its resemblance to drawings from a cyclical drawing tool [ http://www.wordsmith.org/~anu/java/spirograph.html ], planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] IC 418 shows patterns [ http://www.arch.usyd.edu.au/~rob/study/publications/caadria01/2001SaundersGeroCAADRIA.html ] that are not well understood. Perhaps they are related to chaotic winds [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] from the variable central star, which changes brightness unpredictably [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...320..125H ] in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 [ http://www.skyhound.com/sh/archive/jan/IC_418.html ] was probably a well-understood star similar to our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. Only a few thousand years ago, IC 418 [ http://www.seds.org/~spider/ngc/ngc.cgi?IC418 ] was probably a common red giant [ http://www.historyoftheuniverse.com/starold.html ] star. Since running out of nuclear fuel [ http://csep10.phys.utk.edu/astr162/lect/energy/ppchain.html ], though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], visible in the image [ http://heritage.stsci.edu/public/2000sept7/displayic418.html ] center. The light from the central core excites surrounding atoms [ http://www.pbs.org/wgbh/aso/tryit/atom/ ] in the nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] causing them to glow. IC 418 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...319..161K ] lies about 2000 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away and spans 0.3 light-years across. This false-color image [ http://heritage.stsci.edu/public/2000sept7/ic418table.html ] taken from the Hubble Space Telescope [ http://www.stsci.edu/hst/ ] reveals the unusual details. |
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Infrared Ring Nebula
| Title |
Infrared Ring Nebula |
| Explanation |
The classic appearance of the popular Ring Nebula [ http://www.seds.org/messier/m/m057.html ] (aka M57) is understood to be due to perspective - our view from planet Earth looks down the center of a roughly barrel-shaped cloud of gas. But graceful looping structures are seen to extend even beyond the Ring Nebula's familiar central regions in this false-color infrared image [ http://www.spitzer.caltech.edu/Media/releases/ ssc2005-07/ssc2005-07a.shtml ] from the Spitzer Space Telescope [ http://www.spitzer.caltech.edu/about/ now.shtml ]. Of course in this well-studied example of a planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ], the glowing material does not [ http://antwrp.gsfc.nasa.gov/apod/ap040424.html ] come from planets. Instead, the gaseous shroud represents outer layers expelled from a dying, sun-like star. By chance, spiral galaxy IC 1296 is also visible in the upper right of this Spitzer view toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Lyra.html ] Lyra [ http://www.astrosurf.com/lorenzi/images/lira.htm ]. The central ring of the Ring Nebula is about one light-year across and 2,000 light-years away. However, galaxy IC 1296 much bigger [ http://antwrp.gsfc.nasa.gov/apod/ap030516.html ] and hence farther away ... about 200 million light-years distant. |
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Planetary Nebula Mz3: The An
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| Title |
Planetary Nebula Mz3: The Ant Nebula |
| Explanation |
Why isn't this ant a big sphere? Planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ] Mz3 is being cast off by a star similar to our Sun [ http://www.nineplanets.org/sol.html ] that is, surely, round. Why then would the gas that is streaming away create an ant [ http://en.wikipedia.org/wiki/Ant ]-shaped nebula that is distinctly not round? Clues might include [ http://www.spacetelescope.org/news/html/heic0101.html ] the high 1000-kilometer per second speed of the expelled gas, the light-year [ http://starchild.gsfc.nasa.gov/docs/StarChild/ questions/question19.html ] long length of the structure, and the magnetism [ http://www-istp.gsfc.nasa.gov/Education/Imagnet.html ] of the star visible above [ http://heritage.stsci.edu/public/2001feb/display.html ] at the nebula's center. One possible answer is that Mz3 [ http://heritage.stsci.edu/public/2001feb/table.html ] is hiding a second, dimmer star that orbits close [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ] in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field [ http://antwrp.gsfc.nasa.gov/apod/ap980629.html ] are channeling the gas. Since the central star appears to be so similar to our own Sun, astronomers [ http://www.aas.org/education/publications/careerbrochure.html ] hope that increased understanding of the history of this giant space ant [ http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2064.html ] can provide useful insight into the likely future of our own Sun [ http://antwrp.gsfc.nasa.gov/apod/sun.html ] and Earth [ http://antwrp.gsfc.nasa.gov/apod/earth.html ]. |
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PKS285-02: A Young Planetary
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| Title |
PKS285-02: A Young Planetary Nebula |
| Explanation |
How do planetary nebulae [ http://zebu.uoregon.edu/~imamura/208/feb22/feb22.html ] acquire their exquisite geometrical shapes [ http://antwrp.gsfc.nasa.gov/apod/ap981101.html ]? To investigate this, astronomers used the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap950810.html ] to image several young planetary nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap971223.html ]. These nebulae are the outer envelopes of stars like our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ] that have recently been cast away to space, leaving behind a core fading to become a white dwarf [ http://www.star.le.ac.uk/~npb/yearbk.html ]. In this photograph [ http://wfpc2.jpl.nasa.gov/~idt/sahai_aas99/aas99.html ] in red H-alpha [ http://sohowww.nascom.nasa.gov/explore/glossary.html#HYDROGEN_ALPHA ] |
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