Sun is mostly iron, not hydrogen???

http://www.spaceflightnow.com/news/n0201/10ironsun/

"For years, scientists have assumed that the sun is an enormous mass of hydrogen. But in a paper to be presented today at the American Astronomical Society's meeting in Washington, D.C., Dr. Oliver Manuel says iron, not hydrogen, is the sun's most abundant element."

"We think that the solar system came from a single star, and the sun formed on a collapsed supernova core," Manuel says. "The inner planets are made mostly of matter produced in the inner part of that star, and the outer planets of material form the outer layers of that star."

"Manuel says the solar system was born catastrophically out of a supernova -- a theory that goes against the widely-held belief among astrophysicists that the sun and planets were formed 4.5 billion years ago in a relatively ambiguous cloud of interstellar dust."

 

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http://sciforums.com/t4080/s/thread.html

If this were the case I would think that we would have less time left for the sun's estimated lifetime. Original estimates are based on what is believed to be the makeup of the sun's core. Iron is the end element that can not be burned as fuel. The ignition temperature is simply too high.

This theory does answer one thing that has bothered me and I thought I had an answer for. That is, why is it the inner planets are rocky in composition and the outer planets gaseous? I had thought that the answer lay in the early formation stage. That light pressure for the sun would have stripped the lighter elements for the coalescing mass and leave the heavier elements in place. Later the gravitational pull of the body would overcome light pressure and trap some of the gas so that those elements did remain in smaller quantities. Larger planets would have formed their gravitational pull earlier, as the mass collapsed, and being farther out would have taken longer for the movement of any lighter particles. Likely, that the giant planets would not have lost much in comparison to the inner planets.

Interesting topic...

 

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Playing to Occam's Razor, the theory depends upon an additional level of complexity not needed by other, equally descriptive solar system formation theories.

It is obvious that the theory's authors have been perhaps too invested in the idea over several decades to be completely objective and non-biased in the interpretation of the data.

 

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More info on strange helium

http://www.umr.edu/~om/picpages/JRANC-xenonpaper.html

 

We are made of star dust

Of course, what Sagan meant by that is that ALL elements heavier than about H are made in Supernova. So I think it is a given that Astrophysicists have long assumed a Supernova was involved in our formation.

If you look at various models of Spiral Galaxy evolution (so called stochastic models) Supernova are used as the catalyst for starting gas clouds to collapse. The immediate stellar neighbourhood is thought to be formed from a Supernova remnant. As can be seen on this map of our neighbourhood

My major issue with this hypothesis is that it assumes supernova remnants (SNR's) are made of Iron. It is true that a star goes supernova when its core starts prducing Iron. As there is no energy gain from fusing Iron. But you either get a Neutron star or Black Hole as a remnant. You simply do not see large (stellar core sized) lumps of Iron in space.

 

The very next day...

http://spaceflightnow.com/news/n0201/11starform/

All of the stars in the Milky Way, including the Sun and the solar system, plus the stars in neighboring galaxies, were made in giant clouds of molecular hydrogen (H2) and other molecules.

When the stars ignite, the released energy rips the molecular cloud apart, revealing the newborn stars.

This report was presented this week at the American Astronomical Society Meeting in Washington, D.C., by Rosolowsky, Blitz, Greg Engargiola and Richard Plambeck -- all from UC Berkeley.

The debate heats up. We need to put these guys in the same arena with "Mr. IronSun," Dr. Oliver Manuel and have them drop the gloves and go at it!

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Where is Reign_of_Error when you need him?

I'm sure he could explain his understanding of a star and it's makeup, as he once pointed to me the same reasoning that Wet1 Pronounced.

I could assume a few thingsto explain why the Heavy and denser particles end up at the centre, but it involves a mixture of old philosophising and Meta-physics.

Earthquakes on the planet are known to cause Liquidfication, if the ground is wet. (water is forced to the surface).

gold panners (the people that stand in rivers and pan for gold) for years have seen that if you place large objects upon smaller ones (pebbles upon sand) the sand floats to the top.

(the same can be said with Wheat and Chaff)

The lighter elements would of course end up on the outside shells due to viscosity (the friction of elements causing the atmosphere of higher levels to be moving enough to allow them to rise).

Now there are many questions about Solar behaviour that can be asked, as for instance our planet has a Molten Magma which due to planetary spin is kept at a constant viscosity.
I would actually say that the sun too has it's own forms of spin incorporated into it, but caused by gravitational relationship with orbiting bodies. (dopplers of gravity, similar to how a magnet under a table can move iron fillings)

Of course since Orbits are never exactly the same, and involve fractally changing eliptical patterns (which each pass the acumilated gravitation position defines how wide the next elipse will be, and how much speed gain or loss is attributed to it, not to mention planetary polar position)

These passes cause pressure changes on the surface of the sun, and possibly even polarity changes of whole sections of molten gas streamed surface and occasionally errupt into sun spots.

(sometimes of course sunspots can be due to asteriods, and meteors inflicting a direct collision, and their materials flaring up as they become engulfed)

I haven't written any of this to undermine peoples understanding of what occurs, just to broaden upon it, so others might imagine the universe.

 

Re: We are made of star dust

Now I dont think that is entirely correct. If I am not mistaken whe hydogen is burned in the sun then it turns into helium which is used as a fuel source when the sun runs out of hydrogen. Thats what transforms it from its regualr state. Finally it cant use the more complex elements for fuel and supernovas or makes a black hole or turns into a white dwarf , ect, ect, ect. Im a little rough on astronomy so bear with me. Mr. G is the smart astronomer along with wet1.

 

My bad for grossly over simplifying a very complex issue. The explanation that follows is largely from memory so there is bound to be a few foul ups.

The initial ratio of H, He and Li is set in the Big Bang. This in fact forms a test of Big bang models. The early Population I stars are then formed out of H and He. It is from the suernova remnants of these Pop I stars that the interstellar medium is seeded with heavier elements.

There are thought to be two main processes for nuclear fusion in stars. The Proton-proton (ppp)chain and Carbon-Nitrogen-Oxygen (CNO) chain. The latter is only possible in higher mass stars as it takes a lot of energy. Stars like the Sun rely mainly on the proton-proton chain.

So, for the Sun and similar stars the core is a mix of H and He with nuclear reactions converting H to more He. As this happens the core slowly cools and contracts. When there is insufficient H to keep producing He and energy, hydrostatic equilibrium is lost, the core suddenly shrinks, heats and He is now able to fuse to higher elements. It is soon after this that the Star enters the Red Giant branch, looses its atmosphere as a planetary nebula and the core is left to simply die off. The details depend on exact compositions of the core and stellar masses. This is an example of 'slow' reaction process or s-fusion.

For larger mass stars the process of collapse and heating can continue. For these stars the end point is a white dwarf when gravity collapses the core so much that electron shells are in effect touching. Collapse is stopped by 'electron degeneracy pressure'.

For higher mass stars that use the the CNO reaction H is again converted to He but using C, N and O as a type of catalyst. As more energy is needed for this the core runs out of energy a lot more rapidly than above. But, as the star is heavier it is able to create more heat in the core as the core colapses. That is, the core looses heat, collapses and heats to burn He. It again colapses and heats to burn Li and so on up the elements. The process stops when Fe is being produced. This is because Fe can not be fused. At this stage the core, when it collapses again can not generate more heat to maintain hydrodynamic equilibrium. Gravity takes over and the core collapses violently. This time, when electron shells start touching degeneracy pressure is not enough to hold the core up against gravity. The EM forces between atoms is overcome and atoms turned into free nuclei and elecrons. This allows the remaining material to violently and suddenly start fusing all and any available material. This creates vast amounts of neutrinos that 'blow' the atmosphere off. This is the Supernova type II. The atmosphere also starts fusing due to the energy released. The fusing atmosphere is an example of a rapid fusion process.

It is this r-fusion that allows elements above Fe to be created. The sheer eneergy involved is truly phenomenal.

What of the core? As you have free nuclei fusing and lots of free electrons they combine and form neutrons. The core turns into pure neutrons, a neutron star. if the core is above the 'chandrasekhar limit' even the strong nuclear forces are overcome and a black hole formed.

So, the end points for Supernovas are neutron stars or black holes, born out by observation.

I can see why some one might think that a core of 'iron' is produced but it is a long stretch to posit that our Sun has an Iron core and this heats the atmoshpere.

 

We think that the solar system came from a single star, and the sun formed on a collapsed supernova core... Based on these findings, they concluded that the solar system formed directly from the debris of a single supernova, and the sun formed on the supernova's collapsed core. Dr. Oliver Manuel

All of the stars in the Milky Way, including the Sun and the solar system, plus the stars in neighboring galaxies, were made in giant clouds of molecular hydrogen (H2) and other molecules. Rosolowsky, Blitz, Greg Engargiola and Richard Plambeck


Thed, your explanation is the process I'm sure most have come to agree upon, myself included. IMO, the above bold print would be the flaw. But there may be *some* truth to it. The two theories might be combined.

If the supernova explosion were violent enough, the core might be blown up into smaller fragments. If not, then the outcome would be as you've described, neutron star or black hole. I don't believe the sun could form around the remnant core. But if there were only fragments left over, these fragments could be the basis for forming the new core of a proto-system.

If the exploding supernova, as Manuel contends in his article, were to take place in or around the "giant clouds of molecular hydrogen (H2)," as Rosolowsky, Blitz, Greg Engargiola and Richard Plambeck contend in their article, the explosion might trigger the cloud into rotation, or at least movement to some degree. The heat from the explosion would heat up the clouds of hydrogen. The heavier elements from the debris of the supernova would begin attracting the heated hydrogen particles. They would 'seed' the hydrogen clouds. Coupled with the movement or rotation initiated by the exploding supernova, the proto-system would begin to form.

 

Hmmm

Flamethrower now you have me thinking, a bad thing if ever there was one.

Assuming for a moment that the Sun, and by inference, other stars are formed around fragments of exploded supernova remnants we need to explain how a stellar core explodes and fragments.

Conventional wisdom says that either EM/strong nuclear forces stop the collapse of a core, or they do not. What you would need is a case where the inner core produces enough energy that the outer shell explodes.

After a bottle and bit of wine (cheap, nasty German stuff) I can't think of any feasible mechansism. Maybe a core that turns into a quark-guon plasma and the rest rebounds?

Seems to me that this may happen but only in a few rare cases.

If this was a common event you would not see the 'eggs' in the Eagle Nebula (Herzig-Haro objects?) and things like T-Tauri stars.

Ideas? to be knocked down.

 

Thed
we need to explain how a stellar core explodes and fragments...Seems to me that this may happen but only in a few rare cases.

Mr. G
Playing to Occam's Razor, the theory depends upon an additional level of complexity not needed by other, equally descriptive solar system formation theories.

Perhaps we might need to take the approach that there *is* more than one 'template' required for proto-star and proto-system formation. In fact, the supernova theory may be the deciding factor as to whether a proto-star or a proto-system forms.

A proto-star may only form under the conditions present within Giant Molecular Clouds. That being simply the coalescing of molecular hydrogen under its own gravity. The proto-system on the other hand may require both the GMC and a supernova in order to form.

Indeed, our Solar System may very well be a "rare case."

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flamethrower

I'll need some time to think about what you posit. Take it as a given that you have a point. The existing theories of star formation may well be highly deficient and, as I've said many a time, reality is always more complicated than we think.

But, going back to the very first star formation era, they had no supernova remnants to form from. The only, currently, feasible mechanism would be gravitational collapse of the ISM.

Fuel for thought.

 

thed

But, going back to the very first star formation era, they had no supernova remnants to form from

That might lead us to conclude there were no proto-systems in the early universe. Only stars. Proto-stars would have had to form long enough to fuse the heavier elements, complete their cycles and go supernova before a proto-system would have an opportunity to form.

 

http://spaceflightnow.com/news/n0201/13disk/

Astronomers say they have discovered what may be "planetesimals" -- precursors of Earth-like planets -- forming at Earth-like distances and temperatures around a Sun-like star 430 light years away.

Members of the present team Backman and Herrera independently identified the HD 113766 system as being especially interesting because much of the circumstellar material has comfortably Earth-like temperatures around 300 degrees Kelvin (80 Fahrenheit).

The HD 113766 system, estimated to be about 10 million years old, does not show evidence of a massive hot gas+dust disk like the one around the prototypical very young Sun-like star T Tauri.

Rather, it appears to be in a subsequent developmental stage in which the gas has mostly dispersed and solid particles are supposed to be accumulating into asteroid- and planet-sized objects. Planetary formation models indicate that at an age comparable to this system, Jupiter and Saturn were mostly finished, but the Earth and its neighbors in the inner solar were only partly constructed.HD 113766 is similar to another famous inner debris disk system surrounding one component in a multiple star system, HD 98800. Why one component in each system appears to harbor a circumstellar disk system and the other does not is still a mystery.

"Although there is no direct evidence for planets surrounding HD 113766, the observations suggest the emergence of a planetary system not unlike our own."

The plot thickens!

 

Two things here I think

Star formation and Solar System formation.

As I mentioned before the first generation of stars formed without 'seeds' by gravitational collapse and conservation of angular momentu. So by wielding Occams razor it is fair to assume recent stellar populations form the same way. Either an existing gas cloud collapses, is shocked by a supernova to collapse or a supernova creates a gas cloud that then collapses. Saying that, it might not be the only method. I'll accept the Universe is a lot more weird than we know yet.

Solar systems are more fun. Recent observations of star forming regions clearly show gas/dust discs around new stars. Yet the above posted by Flamethrower adds an interesting slant on things.

The problem with Solar System formation, as I see it, is to explain why the inner planets are Iron/Silicon, the Outer planets gas giants and the Sun largely gas. This apparently contradicts the model of 'heavy elements' gravitating towards the center, so how is the Sun formed?

Just has an idea about this largely revolving around concepts of escape velocity and the velocity of free gases. Assume for a moment you have a reasonably isotropic gas cloud. A nearby supernova shocks the cloud in one direction making it inhomogeneous. The now slightly larger mass has higher gravity and starts collapsing. Gas molecules have a valocity based on temperature and mass. Some escape gravity, some do not. The center coalesces and starts to form a stellar core. Larger mass elements (having lower free velocities) are pulled towards the center. Some lower mass molecules (H and He) have sufficient velocity not to be pulled into the center.

This way you get a core of largely gas, stratification of element abundances (also depending on initial composition) with lower mass molecules towards the outside. That is, gas giants on the outer edges, rocky planets towards the center and the majority of mass (90%+) in the middle.

Does that sound right?

 

Thed,

That sounds pretty good. Let me take a shot.

We would presume that a gas cloud would begin to coalesce into a proto-star as you've described. The temperature of the hydrogen molecules would be higher where the gas had coalesced to a denser region than the rest of the cloud, probably close to the center. The cloud should also be in rotational motion by this time.

A supernova would heat up hydrogen molecules in another region of that cloud, possibly with higher temperatures than that of the central region and more than likely not anywhere near that central region. It may also trigger a change in the direction of movement of the cloud, either adding to the momentum or changing it altogether. IMO, the central region would be little affected by the supernova.

Now you have a gas cloud with two regions of hotter, denser hydrogen molecules moving in somewhat different directions than what originally transpired. Perhaps now there are two regions that begin to revolve around each other within the gas cloud. The supernova heated region would be a smaller region and would revolve around the much larger central region. Heavier elements from the supernova would get injected into the gas cloud.

Now then, do the two denser regions begin to coalesce together or do they form separately? IMO, the central region would continue coalescing to form a star and the other region eventually forming the gas giants. Heavier elements, heated by the supernova and although injected into the cloud, would for the most part remain near the supernova heated region and eventually form the rockier planets.

With this model, the supernova heated region of the gas cloud that contained heavier elements would actually be the region that forms the planetary system. It would form this system without the need of any interaction with the central region. The central region of heated gas would simply continue to form a star with perhaps a few modifications based on receiving some heavier elements from the supernova.

The question remains, what happens to the spent core of the supernova? In our solar system, could this be the core of Jupiter or one of the other gas giants? I think I'm stretching it here. My astrochemistry is not up to par.

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S'ok

Seems to me the above model would result in terrestial planets on one side of a system, gas giants on the other. Given time there would be an apparent random spread of planets.

The problem with using fragments of a SNR for nucleation points is still one of, how are the fragments produced? You (not you personally) need a method by which parts of a condensed core are blown off the remnant against the forces of gravity and/or strong nuclear forces. I'll be honest, I simply can not visualise this happening. Imagine it, yes, think of a way of it happening, no.

If you want, take this to E-Mail. My mail address should be public.

 

Take it to email? But, but, interested lurkers would miss out…

 

thed, flamethrower ...

Please keep it 'public'. Don't have anything to contribute, but am enjoying.

Take care.