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Post Info TOPIC: Supernova Remnant N 63A


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RE: Supernova Remnant N 63A
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DEM L316.kmz
Google Sky file (1kb, kmz)

Position (J2000) RA 05h 47m 15.00s | Dec -69 42' 25.00"

-- Edited by Blobrana at 14:49, 2008-01-12

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DEM L316
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The Gemini South Multi-Object Spectograph (GMOS) recently captured a dramatic image of a vast cloud complex named DEM L316 located in the Large Magellanic Cloud. The peanut-shaped nebula appears to be a single object, but the latest research indicates that it is really comprised of two distinct gas and dust clouds formed by different types of supernova explosions.

DEML316
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Credit Gemini Observatory / Multi-Object Spectrograph (GMOS-South)

Newly released optical image of DEM L316 made with GMOS on Gemini South. This image was obtained as part of the Gemini Legacy Imaging Survey which is led by: P. Michaud, S. Fisher, and R. Carrasco from Gemini and T. Rector from the Univ. of Alaska at Anchorage.

Full-Resolution TIFF | 12.1mb
Full-Resolution JPEG | 672mb
Med-Resolution JPEG | 348kb


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Supernova Remnants DEM L316
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The mysterious double-lobed structure called DEM L316 appears to be made of two supernova remnants.

However, supernova remnants are not usually found in pairs it is difficult to envisage how the double structure formed.

"I've been looking at this pair for a while now and it's always been a bit puzzling" - Rosa Williams, team member and astronomer at the University of Illinois at Urbana-Champaign, US.

Observations with the Japanese X-ray satellite ASCA in 2001 ruled out the possibility that just one single supernova formed the dual-orb shape when it exploded. The two lobes have different compositions, suggesting they formed from separate stars.

The new observations with Chandra X-ray Observatory confirm these differences.
The lower right part of the structure has significantly less iron than in the upper left one.
The lower region was created when a star more massive than about 10 Suns ran out of nuclear fuel and its outer layers exploded. Its inner layers which produce iron would have collapsed into either a dense neutron star or a black hole, keeping the iron locked out of sight.

The iron-rich upper left orb probably formed from an entirely different type of supernova. That star would have started out as a white dwarf the burned-out ember of a star like the Sun and was stealing material from a nearby companion. When it had grown to more than 1.4 times the Sun's mass, it became too heavy to support its own weight. It then blew itself up completely, producing massive amounts of iron in the explosion that sent material hurtling into space.
Measurements of the velocity of gas in the two regions indicate that they are both at the same distance from the Earth. But it is still not clear whether that is an illusion - the two remnants simply appear to be in the same locality, and are actually at different distances from Earth.

"That's where it starts to get interesting. Having two stars that happen to explode very close to each other in time and space is fairly unlikely" - Rosa Williams.

The puzzle is that massive stars explode in just a few million years, while it takes billions of years to form a white dwarf - the two stars can not have formed together.

"So, if the two formed at the same time, they should not under any circumstances die at the same time" - Rosa Williams.

The question could be settled if astronomers detected dense gas such as neutral hydrogen between the two remnants.

"That could be an indication of a collision of material piling up thickly along the boundary" Rosa Williams.

As yet no telescope has the resolution to detect neutral hydrogen at that distance.

The research will be published in December in the Astrophysical Journal.

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Supernova Remnant DEM L316
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DEM L316: Supernova Remnants Deconstructed
This composite X-ray/optical image reveals a cat-shaped image produced by the remnants of two exploded stars in the Large Magellanic Cloud galaxy in the constellation Dorado.
Although the shells of hot gas appear to be colliding, this may be an illusion.


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Position(2000) : RA 05h 47m 15.00s Dec -69 42' 25.00"
X-ray Image of DEM L316.
The image is 5.7 arcmin across.
Credit: X-ray: NASA/CXC/U.Illinois/R.Williams & Y.-H.Chu; Optical: NOAO/CTIO/U.Illinois/R.Williams & MCELS coll.

Chandra X-ray spectra show that the hot gas shell on the upper left contains considerably more iron than the one on the lower right. The high abundance of iron implies that this supernova remnant is the product of a Type Ia supernova triggered by the infall of matter from a companion star onto a white dwarf star.
In contrast, the much lower abundance of iron in the lower supernova remnant indicates that it was a Type II supernova produced by the explosion of a young, massive star. It takes billions of years to form a white dwarf star, whereas a massive young star will explode in a few million years. The disparity of ages in the progenitor stars means that it is very unlikely that they exploded very close to each other. The apparent proximity of the remnants is probably the result of a chance alignment.

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Supernova Remnant N 63A
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Supernova Remnant N 63A Menagerie
A violent and chaotic-looking mass of gas and dust is seen in this Hubble Space Telescope image of a nearby supernova remnant.
Denoted N 63A, the object is the remains of a massive star that exploded, spewing its gaseous layers out into an already turbulent region.


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Position (J2000): R.A. 05h 35m 43s Dec. -66 02' 32"

The supernova remnant is a member of N 63, a star-forming region in the Large Magellanic Cloud (LMC) in the constellation Dorado.
Visible from the southern hemisphere, the LMC is an irregular galaxy lying 160,000 light-years from our own Milky Way galaxy. The LMC provides excellent examples of active star formation and supernova remnants to be studied with Hubble.
Many of the stars in the immediate vicinity of N 63A are extremely massive. It is estimated that the progenitor of the supernova that produced the remnant seen here was about 50 times more massive than our own Sun. Such a massive star has strong stellar winds that can clear away its ambient medium, forming a wind-blown bubble. The supernova that formed N 63A is thought to have exploded inside the central cavity of such a wind-blown bubble, which was itself embedded in a clumpy portion of the LMC's interstellar medium.

Images in the infrared, X-ray, and radio emission of this supernova remnant show the much more expanded bubble that totally encompasses the optical emission seen by Hubble. Odd-shaped mini-clouds or cloudlets that were too dense for the stellar wind to clear away are now engulfed in the bubble interior. The supernova generated a propagating shock wave, which continues to move rapidly through the low-density bubble interior, and shocks these cloudlets, shredding them fiercely.

Supernova remnants have long been thought to set off episodes of star formation when their expanding shock encounters nearby gas. As the Hubble images have illustrated, N 63A is still young and its ruthless shocks destroy the ambient gas clouds, rather than coercing them to collapse and form stars.
Data obtained at various wavelengths from other detectors reveal on-going formation of stars at 10 to 15 light-years from N 63A. In a few million years, the supernova ejecta from N 63A would reach this star-formation site and may be incorporated into the formation of planets around solar-type stars there, much like the early history of the solar system.

The Hubble image of N 63A is a colour representation of data taken in 1997 and 2000 with Hubble's Wide Field Planetary Camera 2. Colour filters were used to sample light emitted by sulphur (shown in red), oxygen (shown in blue), and hydrogen (shown in green).




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