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BigDon
2009-Jan-31, 06:42 AM
When heavier elements like gold and trans-uranic metals are created in major core collapse supernovas, how does the new matter express itself into reality? I can picture the other elements being created in the interior but after wards, when the "stuff" is being flung I sort of lose the picture.

I know on Earth we get veins of metals due to thorium and gravity heating seperating the metals out, but in the primoidial cloud, prior to it's collapse into ...us, were these metals in a vapor state, a serious plasma or like a cloud of ball bearings or large chucks the size of California? (At least the non-reactive stuff)

I guess that's all time dependant, with cooling a big factor.

Oh and when highly reactive matter is created "in abundance" in energetic events how do the rules of fission apply? Is that a seperate phase of the explosion or is this indistinguishable from the "main event"? (Or indeed part of it)

mugaliens
2009-Jan-31, 07:35 PM
I dunno, BD, but these are great questions. We're in for an interesting couple of days as the answers roll in!

Pass the popcorn...

BigDon
2009-Jan-31, 08:17 PM
Maybe a clarification is in order.

Does an existing outbound lump of matter transform due to energies overtaking it and thus become other elements? Or are there other mechanisms for matter creation at un-Earthly energies?

Does the extreme gravity changes alter how material is created, (Is transmuted a better term?) or is this a function mainly of temperature and particle bombardment alone?

In core physics are there different maths for gravity and pressure once you are knee deep in it? Or do they become kind of the same thing at some point?

Though I only presume there are fantastical, from my frame of reference, gravitic changes when one of the "Big Blues" goes all irony, (which is not lost on me) and the major shrinkage occurs. With that all important "opaque to neutrinos phase" that's there just to keep the maths interesting and furniture movers out of stellar physics.

EDG
2009-Jan-31, 08:19 PM
I'd suspect the supernova ejecta would impact nearby protostellar clouds and just deposit the new elements as individual atoms on the surface of its dust grains - and the impact of the ejecta wave may even initiate the collapse of the cloud into a star and planetary system.

After that, when the planets that form start heating up and differentiating, things will get separated out and then other processes would concentrate them as veins or whatever in the crust of the new planet.

Lord Jubjub
2009-Jan-31, 09:33 PM
That is my understanding--that the shock wave for the initial core collapse creates massive collisions involving massive amounts of energy. I would ask an additional question:

What is likely the heaviest element created (even if it decays femtoseconds after creation)?

EDG
2009-Jan-31, 10:20 PM
http://en.wikipedia.org/wiki/Supernova_nucleosynthesis claims that the highest element known to be fused in a supernova is Californium (mass 254), an artificial element on Earth.

korjik
2009-Jan-31, 11:21 PM
One thing about supernovae:

Most of the heavier elements probably come from type Ia supernova. A type Ia is a white dwarf that starts carbon burning when the mass gets too high. Basically, the white dwarf accretes mass from another star, then when it hits the limit, carbon starts fusing.

The start then goes boom. Thought to be completely destroyed. All the matter and energy released.

Most nucleosynthesys is done by absorbing neutrons. As far as I remember, there is no real limit on the size of the atom made, but really big atoms wil come apart pretty quick.

astromark
2009-Feb-01, 12:33 AM
Most of us have difficulty understanding the state of matter at the Big Bang. I do not see much difference from that to what is happening deep inside of a Nova event. Yes I know there is a massive energy transfer. Yes, and just a few billion tons of gravity force. I will at this point make a stand. I reject the word create being used. It conjures up all the wrong conceptions regarding the formation of elements., and yes I do understand that the BB was and had little to do with the formation of the heavy metals that we know of now. Searching out heavy metals and under what circumstance they might be formed. Nebulous gasses and gravity and pressure and, and. Some raw material to start with. As hard to imagine as it is that a coalescing cloud of loosely bound gas can become a super massive black hole. That with it will come some very exotic heavy metals... That is the very nature of nature. Search out your atomic tables... Those really big numbers are the ones you seek. Are they stable? No. Easy to find ? No., common ? No.

trinitree88
2009-Feb-01, 06:06 PM
Big Don. There are two paths to nucleosynthesis, generally speaking, the slow process...s-process...in the sun, main sequence stars, and red giant CNO synthesis stars................AND........the rapid process, or r-process, which occurs in supernovae of all types, not just core collapse, and in presumably neutron star mergers. The following by Cowan et al is a pretty good summary from Physics Today. pete see:http://theory.gsi.de/~petermann/papers/cowan-thieleman-ptoday.pdf

and see:http://en.wikipedia.org/wiki/R-process

as for the distribution of the elements, thats not homogeneous, as was once assumed. The explosions are convoluted and mixed, like vegetable soup. Eventually when the expanding debris cloud reaches a velocity of ~ 25-30 km/sec, dust grains will aggregate. Just as you could melt the Earth if you got to play God, and slowly increase global warming by 10 degrees per day, Kelvin....the last thing to melt would be things that you line ceramic ovens with...refractory materials. In reverse order, once the Earth was melted, as it cooled,(God turns down the thermostat now) they would be the first to solidify. So, when hot dust cools, the first thing to form grains are refractory materials with very high melting points...pyroxene, olivine, quartz, etc. The last thing to solidify would be the light gases, hydrogen and helium...provided the pressure matches the phase diagram allowances.
One of the experts in this area is Eli Dwek of Nasa, Goddard, Greenbelt,MD. Another is Draine.

see:http://eprintweb.org/S/authors/All/dw/Dwek/2
see:http://nedwww.ipac.caltech.edu/level5/March04/Draine/frames.html

There is a tiny bit of nucleosynthesis that occurs when gamma ray bursts photodissociate nuclei in space..(it takes about 10-15 Mev photons) ..and the free neutrons can mix it up with whatever is around, but this is pretty small pickings. pete
pete

mugaliens
2009-Feb-02, 08:43 PM
Does an existing outbound lump of matter transform due to energies overtaking it and thus become other elements? Or are there other mechanisms for matter creation at un-Earthly energies?

Supernova nucleosynthesis results during explosive oxygen and silicon burning. By "burning," I'm referring to fusion, which is both driven by the supernova event itself, and in turn adds to it. For that process, see supernova (http://en.wikipedia.org/wiki/Supernova).

Once the supernova explosion begins, the wave front expands at velocities up to 10% of the speed of light, creating fusion-ripe temperatures and pressures. Whatever elements have not fused into heavier ones do so now, adding tremendously to the wave front, heat, pressure, and particle-rich environment.


Though I only presume there are fantastical, from my frame of reference, gravitic changes when one of the "Big Blues" goes all irony, (which is not lost on me) and the major shrinkage occurs. With that all important "opaque to neutrinos phase" that's there just to keep the maths interesting and furniture movers out of stellar physics.

It's not the gravity, just heightened (and relativistic) temps and pressures which perpetuate a hyper-accelerated fusion process.