A supernova caught early

Joined : 26 Jan 2008 Posts : 63

http://www.space.com/scienceastronomy/080612-star-burst.html#comments

P 460: 5. SOLAR RADIATION
That the suns of space are not very dense is proved by the steady streams of escaping light-energies. Too great a density would retain light by opacity until the light-energy pressure reached the explosion point. There is a tremendous light or gas pressure within a sun to cause it to shoot forth such a stream of energy as to penetrate space for millions upon millions of miles to energize, light, and heat the distant planets. Fifteen feet of surface of the density of Urantia would effectually prevent the escape of all X rays and light-energies from a sun until the rising internal pressure of accumulating energies resulting from atomic dismemberment overcame gravity with a tremendous outward explosion.

Allen

Subject: Re: A supernova caught early Mon Jun 16, 2008 4:33 am

Thanks Allen! Here's the article:

Cosmic Grim Reaper Seen For First Time
By Jeanna Bryner
Senior Writer
posted: 12 June 2008
02:01 pm ET

Like a cosmic Grim Reaper, a blast of ultraviolet light signals the violent death of the universe's most massive stars. Now astronomers have viewed this heavenly harbinger for the first time.

"Astronomers have been dreaming about seeing the first light from the violent death of a star for over 30 years," said lead researcher Kevin Schawinksi of the University of Oxford. "Our observations open up an entirely new avenue for studying the final stages in the lives of massive stars and the physics of supernovae."

Schawinksi and his colleagues detected the ultraviolet signal of a hefty star on the verge of explosion, which they detail in the June 13 issue of the journal Science.

Usually, when astronomers see a supernova, the star has already been destroyed. "It's very hard to tell much about precisely the kind of star that actually died there," Schawinski told SPACE.com. "The really cool thing about our observations is this light traveling ahead of the shock wave traveled through the star before it was destroyed."

He added, "It's telling us about the properties, the conditions, of the star at the moment it died, but before the shock wave actually disrupted it."

Doomed star

When a massive star, weighing at least 10 suns, runs out of nuclear fuel, it can collapse under its own weight, triggering an explosion called a supernova. The explosion sends the stellar guts spewing away at 20 million mph (10,000 km/sec) in a fireball that's a billion times brighter than the sun, the researchers say.

It's this fireball that scientists observe. What they haven't seen until now are the final moments of the doomed star just before the visible explosion. For the past 30 years or so, theorists have predicted a surge of ultraviolet light should come before the actual visible explosion.

There are several problems for actually seeing this phenomenon. "By the time you see the supernova, it's already days or weeks in the past," Schawinski said. "If you see a supernova you'd have to go back in time. You'd have to be already looking at the position."

The other issue is the fact that Earth's atmosphere absorbs ultraviolet light, and so you'd need a space telescope to actually be able to view the death beacon. The space telescope GALEX, which orbits Earth about every 98.6 minutes and views the universe in ultraviolet, was the answer.

With GALEX, researchers recently got front-row seats to the pre-show of what they suspect was a red supergiant star measuring somewhere between 500 and 1,000 solar radii on the verge of explosion. A red supergiant is a hefty star nearing the end of its life that can swell to 100 times its original size before exploding.

Schawinski and his colleagues looked at GALEX images taken at the positions of supernovae previously identified with optical telescopes in Hawaii.

"We found a new source at the location of one supernova, suddenly outshining its galaxy host in the UV," said Mark Sullivan of the University of Oxford. "It appeared a couple of weeks before the optical discovery of the supernova and marked the first stage in the death of the star."

The final hours

The UV peak represented a unique phase in the formation of the supernova SNLS-04D2dc, just before the shock wave from its collapsed core reached the star's surface to violently eject its shell of hot gas.

During a red supergiant's final hours, a shock wave whizzes outward with the related radiation moving even faster and heating up the star's surface. The temperature at the surface ramps up from a few thousand degrees Celsius to several hundred thousand degrees. Just before the shock wave catches up and reaches the surface (triggering a supernova), the star is producing the same total luminosity as a thousand billion suns, the researchers say.

Once the shock wave catches up, it plows through the outer parts of the star, accelerating several suns' worth of material outward. The surface of the star explodes. A few days later, supernova hunters will spot the bright visible light of the explosion.

Schawinski describes the observations as looking inside of a semi-transparent star as it's dying.

"We saw the whole thing. We saw the radiative precursor, this UV light, moving ahead [of the shock wave]," Schawinski said. "We saw that arrive and then the point at which the shock wave comes to the surface and destroys the star. In a sense we could see the shock move inside the star because the light from the shock was moving ahead of it."

The new UV peak findings, the astrophysicists say, will shed light on deathly details once hidden beneath a star's outer cloak.

"This is a whole new avenue into studying the late stages of massive stars," said Oxford researcher Christian Wolf. "Most of what we know today is based on computer simulations. But as always when you test theory against observations for the first few times, we may be in for surprises."

Video: Supernova Destroyer/Creator

Subject: Re: A supernova caught early Wed Jul 02, 2008 10:47 am

Hi everyone!

Yes, paper 41 could certainly be called the astrophysics paper.

We're told: That the suns of space are not very dense is proved by the steady streams of escaping light-energies. Too great a density would retain light by opacity until the light-energy pressure reached the explosion point. There is a tremendous light or gas pressure within a sun to cause it to shoot forth such a stream of energy as to penetrate space for millions upon millions of miles to energize, light, and heat the distant planets (460).

But earlier the same paper and same author tells us: One of your near-by suns, which started life with about the same mass as yours, has now contracted almost to the size of Urantia, having become forty thousand times as dense as your sun. The weight of this hot-cold gaseous-solid is about one ton per cubic inch. And still this sun shines with a faint reddish glow, the senile glimmer of a dying monarch of light (460).

Is TUB trying to tell us this poetic sounding but scientifically unnamed dying monarch of light will go supernova very soon due to its extreme density and increasing opacity?

From the Space.com article in which a massive red supergiant star was caught in the act of becoming a supernova:

Subject: Re: A supernova caught early Thu Jul 03, 2008 7:22 am

http://www4.nau.edu/meteorite/Meteorite/Book-GlossaryH.html

This is called a Hertzsprung-Russell Diagram and it tells the theory of stellar evolution according to modern understanding. Of course, this understanding is not absolute by any means. The key to a star's evolution and placement on this model is its initial mass. Or to put it another way, how much a star "weighs" when it's born determines how long it will shine.
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Subject: Re: A supernova caught early Thu Jul 03, 2008 7:29 am

This diagram courtesy of Atlas of the Universe shows all known stars within 20 light years of our world. There are:

2 Class A stars. Roughly defined as having 1.5 to 3 times the mass of the sun. Sirius (2.3 mass) and Altair (1.8 mass) are both main sequence stars.

1 Class F star. Roughly defined as having 1.1 to 1.5 times the mass of the sun. Procyon (1.7 mass) is a sub-giant star which means it is beginning to run out of fuel and it used to be Class A.

6 Class G stars. Roughly defined as 0.9 to 1.1 times the mass of the sun. The sun (1 mass), Alpha Centauri A (1.1 mass), Tau Ceti (0.92 mass), Eta Cassiopeia ("Achird;" 1.08 mass), 82 Eridani (0.91 mass), and Delta Pavonis (0.98 mass) which may be starting to evolve off the main sequence.

16 Class K stars. Roughly defined as having 0.9 to 0.5 times the mass of the sun. Too many to name, but Epsilon Eridani, 40 (Omicron 2) Eridani "Keid", Epsilon Indi are being targeted for closer scrutiny in the search for habitable planets.

78 Class M Stars. Roughly defined as having less than half the mass of the sun. The vast majority of main sequence stars belong to this class.

There are also 6 white dwarf stars and 8 brown dwarf stars. White dwarfs are about the size of our world and could be called "dying monarchs of light" but none shine with a faint red glow. White dwarfs cannot be more than 1.4 mass of the sun. Because white dwarfs have such mass packed within a volume about the size of earth, they are very dense. This is the fate of stars like the sun in mass perhaps a little bigger. Brown dwarfs are failed stars because they didn't have enough initial mass to start their nuclear fires burning. The mass of this class of object is roughly defined from about 0.08 mass to about 0.02 mass.

Fifteen feet of surface of the density of Urantia would effectually prevent the escape of all X rays and light-energies from a sun until the rising internal pressure of accumulating energies resulting from atomic dismemberment overcame gravity with a tremendous outward explosion (460).

While this statement describes hydrostatic equilibrium, if this were true, then astrophysicists should see burst of x-rays preceding a supernova explosion, not ultraviolet.
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If you embrace the truth, the Truth will Embrace You!