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Post Info TOPIC: SN1006
Blobrana


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RE: SN1006
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SN 1006 was a supernova, widely seen on Earth beginning in the year 1006 AD; Earth was about 7,200 light-years away from the supernova. It was the brightest apparent magnitude stellar event in recorded history reaching an estimated -7.5 visual magnitude.
First appearing in the constellation of Lupus between April 30 and May 1 of that year, this "guest star" was described by observers in China, Egypt, Iraq, Japan, Switzerland, and possibly North America.
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Blobrana


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Supernova 1006
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Title: The Effect of a Cosmic Ray Precursor in SN 1006?
Authors: Cara E. Rakowski, J. Martin Laming, Una Hwang, Kristoffer A. Eriksen, Parviz Ghavamian, John P. Hughes

Like many young supernova remnants, SN 1006 exhibits what appear to be clumps of ejecta close to or protruding beyond the main blast wave. In this paper we examine 3 such protrusions along the east rim. They are semi-aligned with ejecta fingers behind the shock-front, and exhibit emission lines from O VII and O VIII. We first interpret them in the context of an upstream medium modified by the saturated nonresonant Bell instability which enhances the growth of Rayleigh-Taylor instabilities when advected postshock. We discuss their apparent periodicity if the spacing is determined by properties of the remnant or by a preferred size scale in the cosmic ray precursor. We also briefly discuss the alternative that these structures have an origin in the ejecta structure of the explosion itself. In this case the young evolutionary age of SN 1006 would imply density structure within the outermost layers of the explosion with potentially important implications for deflagration and detonation in thermonuclear supernova explosion models.

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Blobrana


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RE: SN1006
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This image is a composite of hydrogen-light observations taken with Hubble's Advanced Camera for Surveys in February 2006 and Wide Field Planetary Camera 2 observations in blue, yellow-green, and near-infrared light taken in April 2008. The supernova remnant, visible only in the hydrogen-light filter was assigned a red hue in the Heritage colour image.

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Blobrana


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Title: X-Ray Spectroscopy of SN 1006 with Suzaku
Authors: Hiroya Yamaguchi, Katsuji Koyama, Satoru Katsuda, Hiroshi Nakajima, John P. Hughes, Aya Bamba, Junko S. Hiraga, Koji Mori, Masanobu Ozaki, Takeshi Go Tsuru

We report on observations of SN 1006 with the X-ray Imaging Spectrometers (XIS) on board Suzaku. We firmly detected K-shell emission from Fe, for the first time, and find that the Fe ionisation state is quite low. The broad band spectrum extracted from the southeast of the remnant is well fitted with a model consisting of three optically thin thermal non-equilibrium ionisation plasmas and a power-law component. Two of the thermal models are highly overabundant in heavy elements and, hence, are likely due to ejecta. These components have different ionisation parameters: n_et ~ 1.4 x 10^{10} cm^{-3} s and n_et ~ 7.7 x 10^8 cm^{-3} s and it is the later one that produces the Fe-K emission. This suggests that Fe has been heated by the reverse shock more recently than the other elements, consistent with a picture where the ejecta are stratified by composition with Fe in the interior. On the other hand, the third thermal component is assumed to be solar abundance, and we associate it with emission from the interstellar medium (ISM). The electron temperature and ionisation parameter are kT_e ~ 0.5 keV and n_et ~ 5.8 x 10^9 cm^{-3} s. The electron temperature is lower than that expected from the shock velocity which suggests a lack of collisionless electron heating at the forward shock. The extremely low ionisation parameter and extreme non-equilibrium state are due to the low density of the ambient medium.

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Blobrana


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The planet Mars was very bright in the constellation Scorpius (constellation of the Rabbit Tracks)- at mag -2.1.

1006-4-30-23h47m

Position(2000): RA = 15h57m59.21s Dec =-21°00'59.0"

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Blobrana


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The Supernova as seen by prehistoric native Americans.

SN1006 from White Tank

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Blobrana


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Navajo Astronomy
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The First Large One (Scorpius)
The First Large One represents everything that is of great and overpowering strength. His attributes are of the male demeanour, strength, daring, protective, non-fearing, provider, comforter, security, enlightenment, guidance and assurance. These are the same characteristics given with prayers to earth, sky, sun, air, water and other stars.
Like all stars, though not always visible, he has an eagle tail feather and cane. His cane is visible, though. The cane represents stability in every aspect of life. When Changing Woman (Navajo Deity), created the four original clans, each was given a cane. The canes were made from turquoise, white shell, abalone shell and black jet.
Canes are used for an aged person or an injured or weak person for stability. Canes are also used in ceremonies. They offer a chance to redirect oneself to their chosen life path.
The story goes that when a cane is needed an offering of corn meal must be placed in the tree for use of one of its branches before the branch is cut. It must be remembered in preparing a cane that the part used for the bottom must be the end that was nearest the roots of the tree. The tip where the leaves grew must be the handle. In this way the cane remains standing, just as when the branch was growing on the tree. The elders’ teachings say this is so because life must continue to grow in the direction it was originally set out.

Rabbit Tracks (Tail of Scorpius)
The Navajo interpret Scorpius as the First Large One. The Tail of Scorpius is also seen as distinct. It is a constellation referred to as Rabbit Tracks. It is said that these tracks have been there since the creation of the universe. This constellation is related to the Huntingway ceremony.
The Rabbit Tracks remain in the southeastern horizon, travelling west. The stars are travelling west, but the rabbit is said to be running in a northeastern direction. The hunting season begins when the tracks tip to the east, it is said the young deer and antelope are no longer dependent on their mothers.
Hunting is a sacred event. It is recognized that hunting is necessary for the people to survive and certain ceremonies have to be followed. This includes cleansing and purifying of the body of the hunter. The dressing, or butchering of the animal must not be done near the home. When the tracks are not tipping east the hunters are to lay down their weapons and stay home.
The Huntingway ceremony is associated with this constellation. It is a male ceremony. Navajo women are not usually hunters. Another ceremony related to this is the Feather ceremony.
The Feather ceremony is a ceremony to cure an individual who has had contact with an animal. Certain animals are to be pets and others are not. Sometimes a person may become ill if they try and make a pet of an animal not intended to be one.
The Tracks are also symbolic to the paths we all must walk in our life. Everything and everyone has their own tracks. All constellations have their own tracks or footprints. In certain ceremonies on earth corn pollen and yellow corn meal is used to make footprints on the ground. This act of making symbolic footprints is to make certain that the order of creation, with all its purpose and significance is maintained. It must be kept sacred, so the people will lead a blessed life and will follow them as their guide.

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Blobrana


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RE: SN1006
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Prehistoric Native Americans may have carved a record of a supernova explosion that appeared in the skies a millennium ago into a rock in Arizona, US.

John Barentine, an astronomer at the Apache Point Observatory in New Mexico, came across the carving while hiking in the White Tank Mountain Regional Park in Arizona.
It depicts a scorpion and an eight-pointed star.

"I had just been reading about the supernova of AD 1006 and I knew it appeared in the constellation Scorpius, so the connection flashed into my mind." - John Barentine.

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Blobrana


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This false-colour Chandra Xray telescope image of a supernova remnant shows X-rays produced by high-energy particles (blue) and multimillion-degree gas (red/green).
In spring 1006 AD, what was thought to be a "new star" suddenly appeared in the constellation Lupus, near the star Beta Lupi, and over the course of a few days became brighter than the planet Venus. The supernova of 1006, or SN 1006, may have been the brightest supernova on record.
The supernova was probably seen first on April 30, 1006, according to records from China and Japan. It was apparently yellow coloured, and visible for over a year, which indicates that the supernova was probably of type II.
The remnant of this supernova was only rediscovered by radio astronomers in the 1960s.
We now know that SN 1006 heralded not the appearance of a new star, but the cataclysmic death of an old one located about 7,000 light years from Earth. It was likely a white dwarf star that had been pulling matter off an orbiting companion star. When the white dwarf mass exceeded the stability limit (known as the Chandrasekhar limit), it exploded.


Expand (222kb, 576 x 576)
Position(2000): RA = 15h 04m 10.01s Dec = -41º 53' 44.88"
Image is 36 arcmin across.

The supernova ejected material at millions of miles per hour, generating a forward shock wave that raced ahead of the ejecta. Particles accelerated to extremely high energies by this shock wave produce the bright blue filaments seen in the upper left and lower right of the image. Why the bright filaments occur only in the observed locations and do not encircle the remnant is not understood. One possibility is that they are due to the orientation of the interstellar magnetic field, which may be roughly perpendicular to the filaments.

High pressure behind the forward shock wave pushes back on the supernova ejecta, causing a reverse shock that heats the ejecta to millions of degrees. The fluffy red features seen throughout the interior of the remnant are from gas heated by the reverse shock. The X-ray spectrum of this gas indicates that it is enriched in oxygen and other elements synthesised by nuclear reactions during the stellar explosion.

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