http://www.sciencedaily.com/releases...0109075137.htm

Any comments from those more knowledgeable than me?


<font size=-1>[ This Message was edited by: ToSeek on 2002-01-09 11:36 ]</font>

Hm.. I guess it isn't impossible...

When I was taking cosmology, the prof gave us the four equations that can be solved to give the interior conditions of a star... Pressure, temperature, gravity, um...mumble... something else... (It's been a while, and I was a maths student...) If the sun had a solid, non-fusing core, the equations would have a different solution, and (in theory) the sun would have different characteristics...

Also, since the sun is, to most appearances, a fairly ordinary, if somewhat brightish, star -- wouldn't the same origin be necessary for all G0 stars?

Heavily dubious...

Silas

That news release says that he has been trying to convince others of that hypothesis for forty years. The evidence for it can't be too strong--maybe the latest is stronger?

Some of his theory isn't really new. Now, is it or is it not true that heavier elements are cooked up in the cores of larger stars and get scattered to the cosmos when those same stars explode? So naturally one could assume that our solar system with its abundance of heavy elements (relative to what? I don't know) came from the dusty remains of an ancient supernova.

What bucks intuition is the implication that our sun then formed around the remaining supernova core. Afterall, aren't the remnant cores of supernova also supermassive, many times the mass of our sun? Aren't they spinning neutron stars, and any mass falling on them would be crushed also to neutron density? Or am I missing something?

I'd have to hope that he's only talking about iron that originally came from a supernova core, scattered to the nine winds, and gravitationally clumped along with all the other star stuff when our sun began to form...

If one phrases it "weakly," sure, it makes sense: the gases in space are richer in iron, now, than 12 billion years ago, and thus newer stars have more iron in 'em than old ones did.

(Just as babies born today have radioactive strontium and cobalt and uranium atoms in 'em because of bomb tests, whereas babies born in 1940 didn't have 'em...)

If *that's* all the guy is saying, then it's old news... So I 'spect he's got a lot more in his bonnet...

Silas

No, he thinks the Sun is mostly iron.

I have many, many problems with this theory. One involves formation: does every star form this way? That implies billions of supernovae, and also brings uip a chicken-and-egg problem; how did the first stars form?

If the Sun is special, why? And why does it look spectrally just like a lot of other GV stars in our neighborhood?

I have not read his paper in detail, but he makes a point of there being too few neutrinoes from the Sun. This is an old problem, and may very well be solved with neutrinoes having mass (they change flavor on thier way from there to here, so we don't detect 2/3 of the ones created int he solar core). And how does his model produce the neutrinoes we do see?

I have been to some, um, alternative talks at AAS meetings (where this was announced) and I am quite sure others brought up these and similar points. I doubt that will make a press release though.

The BA's points have been made and many others have been repeated many many times to the person in question.

He doesn't have a working model for his Iron-Sun, only a basic idea, a disputed interpretation of isotopic ratios, hand waving and back of the enveloppe type arguments. I personally give no credence to his idea until he actually gives quantitative predictions for helioseismology and abundance evolution in the Sun and the solar system.

As far as the Sun being a nearly unique object in the Universe, why not? But then again why? A few isotopic ratios are not convincing when the rest of astrophysics argues against his idea.

I guess the implication would be that only stars with rocky inner planets would be formed this way. Stars without planets or stars with inner gas giants would form by the standard model.

I don't have so much of a problem with the idea that buried deep within the heart of the sun is a core of solid iron plasma. (Wouldn't heavier elements sink to the core of the sun just as they do on other worlds?) And we may never see it or detect it because we can only see the outer shell. But the author suggesting that the main source of heat of the sun comes from gravitaitonal compression of this iron core (like what powers the fires deep within our own world) is a bit of a stretch.
I guess that's why it's here in "Against the Mainstream". eh? [img]/phpBB/images/smiles/icon_smile.gif[/img]

It's interesting to note that one of the first scientific theories of the sun's composition was that it was a ball of iron glowing white-hot due to gravitational compression.

That theory was abandoned in stages; first, because it wouldn't stay hot long enough for the 5 billion year age of the Earth (as deduced from the ages of the oldest rocks); second, spectroscopy showed the sun's light was primarily from ionized hydrogen, with a dash of helium; and third, our understanding of thermonuclear reactions provided an abundant source of energy that would last over geologic time.

I don't think the discrepancies in the current model of solar functioning are large enough to suggest such a radical reinterpretation.

One silly question: if the planets are made from detritus ejected by a supernova, what made it stop so close to the sun? Why isn't it all rushing madly away from the supernova remnant at ludicrouspeed?

I'll take a stab at some serious thoughts here. (adjusts glasses, ahem)

While I'll grant to Dr. Manuel there is a "small" ball of Iron at/near the core of the Sun, I find it highly doubtful that it is a major component.

If the Sun were infact mostly iron I think it would show up in the mass-to-volume (density) ratio. Per my "baby astronomy" class in college, the density of the Sun is consistant with a compsition of 99.XXXX% hydrogen.

Does anybody know if it is possible to calculate if it is possible for the Sun to look/behave as it does, having a mass that is (arbitrarily selected) 51% Iron? I select 51% because it is the minimum whole percentage that permits the Sun to be "mostly iron" as Manuel claims.

I have no scientific calculations to support this but my sense of the "Force" is that the answer is no. An iron ball with 51% the mass of the Sun would have a huge surface gravity and would cause the Hydrogen layers to fuse faster and, therefore, release more energy than is currently observed.

Anybody have any better thoughts?

__________________
It's just one of those damn things of which there are many few. -- Dan Blocker

That's not silly at all! Remember, though, that the first extrasolar planets discovered were around a pulsar, a supernova remnant.

Not all of the star blows outward; there can be a "stalled" part that can recollapse onto the remaining remnant (neutron star). Some theorists think this material can be enough to further collapse the neutron star into a black hole! But there is evidently (literally) enough material that does not escape to form planets in some cases.

Not that I am advocating this guy's theory. I just want to note that some objections to it don't really apply. There are already enough problems with his theory!

Although I agree there is evidence for the possibility of planetary formation after a SN Dr Manuel's idea as he states it requires that the matter from which the planets form are chemically differentiated, i.e. heavy elements near the SN remnant (the proto-Sun) and lighter elements on the edge (to allow the formation of giant planets). AFAIK there is no evidence for this.

On a similar topic, he argues that the Sun was also formed as a chemically differentiated object and not homogeneous as is generally assumed based on our coarse understanding of star formation.

As far as the iron core goes, helioseismology constrains the temperature in the core to better than 1%. The PP reaction rate has a quoted uncertainty of a few percent (5% max if memory serves). If one screws with the chemical composition of the core, one cannot reproduce the seismic Sun. One then has to postulate other wierd stuff such as unforeseen physics dealing with opacity, equation of state or nuclear reactions. While not impossible, it seems improbable. And the more recent solar neutrinos results from SNO would confirm our current understanding of solar physics.

One other point, non-standard models of the Sun can be made for the current Sun. That isn't too hard, just tweak the structure a little and correct the sound speed with other tweaks and so on. The trick is to have the non-standard models agree with the current Sun after 4.6 billion years of evolution when the non-standard physics has a good chance of changing the way the Sun evolves (wrt standard models).

This is not my theory but in the book I am presently reading the author mentions that all stars have cold cores .
He notes that the super giants such as Betelgeux and Antares contradict present theories of star formation because these stars having huge masses somehow did not adhere to the effects of gravity whereby a star such as our sun accumulated its mass and when its supposedly nuclear core ignited then it pushed away the remaining debri to later form our planets .This then he states must mean that gravity has an ignition limit, that is to say that no matter how slow or fast a proto star forms then the pressure is built up to the same point of ignition hence this means that the two huge stars mentioned above accumulated their mass contradictive to gravity and its effects , how then could these two stars acquire their masses ! .

I tend to agree with the author that we presently observe that all things burn from the outside inwards so his theory that stars have cold cores seems feasible to me that the two mentioned stars are not two bloated super giants but just two huge stars whos ignition burning from the outside inwards is only at the molten stage and is then the reason why these stars are red , but hey you make your own mind up or read the book because I am open to all kinds of open minded views and find this alternative theory feasible and I tend to agree in parts or should I say it opens up new areas to investigate .

Emporer, please post the name of the book and its author. I'm curious.

It's true that in most cases one only has direct observations of the surface of stars.
In the Sun however, one has meutrino emission which is emitted directly in the core and which might be held has evidence for a cool, but not cold, central core. Helioseismology is also a fairly direct 'observation' of the solar interior. It is an interpretation of surface observations but the theory is fairly straightforward.

The seismology of other stars is also can also be considered in the same way and more and more stars are studied that way and nothing exceptionally surprising has been found so far.

Finally, looking at many stars in clusters enables us to test fairly accurately stellar models as we compare stars of different mass and evolutionary stages but same age and initial chemical composition.

All the evidence so far points to the fact that our models of stellar structure and evolution are pretty good. I know of no alternative model which even attempts to reproduce the wealth of observations that standard models do.

Bad Bad Astronomer, Phil! You mispelt his name!

The (spelling police 'r us) Curtmudgeon

[quote]
On 2002-01-10 13:03, The Bad Astronomer wrote:
Emporer, please post the name of the book and its author. I'm curious.

Sure but I did provide the link to its introduction to emphasize a point it makes . its at http://www.spaceskeptic.com/ebook/ebook.php it also turns out that their are two site links one being http://www.spaceskeptic.com and http://www.spaceskeptic.co.uk . Have been trying to get back on the site and could only find it through http://www.google.com .

Have tried sending the author a message but their is no link or address except through a private message on the forums , perhaps you may have more luck than me , I registered as starman because I believe I have had contact with the author on another site .

This fails to explain Kuiper belt objects and the Oort cloud, where most of the solar system's non-gaseous mass is located if you don't count the Sun.

I don't see how "strange xenon" could not be formed by a nearby supernova. There seems to be no direct evidence that our own Sun was the producer.

Of course he could be right, but it sounds to me like he wishes the Sun was more unique than it probably really is.

And, of course, it would be a real pain to form gas giants, let alone four of them, under the conditions he thinks formed the Sun.

Emperor, is that book you mention the one by a certain J Reyes? The J Reyes who apparently is also known as Emperor (as pointed out by DStahl)?

<font size=-1>[ This Message was edited by: Argos on 2002-01-16 19:14 ]</font>

"If the Sun is special, why?"

I suppose you could use a version of the Anthropic Principle here. If iron-rich stars are the ones most likely to form rocky inner planets (as opposed to close orbit gas-giants), then given our current understanding, they're the ones most likely to have life in the system able to observe them. Self-selecting really. Just a thought.

__________________
Up the Imps!

"We think that the solar system came from a single star, and the sun formed on a collapsed supernova core," Manuel says.

I can agreeably imagine a slow moving neutron star emmersed in a dense molecular cloud for example, an extended period of time accreting enough material onto itself to become the core of a new star.

I wonder how a necessarily >.88 solar mass neutron star by accretion can, at one solar mass, sustain nuclear fusion reactions for the ~4.5 Billion years of our sun's apparent age, let alone its entire 8 Billion-year history as it evolves off the main sequence toward a cold death.

And shouldn't helio-seismology be able to find such a massive solid at the sun's core in the same way as terrestrial seismology observes the effects of Earth's iron core on propagation of seismic waves across the interior?

<font size=-1>[ This Message was edited by: flamethrower on 2002-01-19 22:52 ]</font>

All stars have cold cores? That's news to anyone who has ever studied stellar structure.

Everything burning from the outside inward? Stellar-structure calculations predict the exact opposite -- nuclear "burning" starts at the center, which is the hottest and most compressed part, and proceeds outward.

Also, the Sun has been shining for something like 4.6 billion years at approximately constant luminosity, which is consistent with continued nuclear reactions, but not with gravitational collapse.

As to massive stars like Betelgeuse and Antares being too massive, my understanding is that there is such an upper mass limit, but that it is something like 60 to 100 solar masses, above the masses of B and A.

Stars with a Heart of Iron. Pg 25 December 2 2003

Early in the evolution of the universe, the lightest of elements are formed in a process called Big Bang nucleosynthesis. The heavier elements are formed within the cores of stars, with the heaviest elements forged from the crucible of exploding stars. The standard model asserts that these heavy elements could only form after the universe was billions of years old, as the result of a heavy star living out its entire life. According to the proposed uniform expansion of space theory, the effect of gravity is so intense near the beginning of time that the entire lifetime of a star could be over in the first million years of the universe’s existence.

The proposed theory addresses one of the concerns that The Bad Astronomer had regarding the Iron core theory proposed by Professor O.K Manuel. A more current link to the professor Manuel’s work is web.umr.edu/~om

The following topics are mentioned in this posting
1. A brief amateur explanation of Professor O.K. Manuel’s work
2. Evidence of Iron distribution and sifting within galaxies
3. Arguments that entirely gaseous stars are unstable
4. Iron cores provide stability
5. Arguments that the mathematical modeling used to presently describe stellar structure may not be that accurate.
6. Future post, quasars and galaxies

Professor Manuel

Part of the problem for Professor Manuel is that he is not part of the Astronomical Club. He is a Nuclear Chemist who analyzed the elements found within meteorites and moon samples. He discovered traces of Strange Xenon. He realized that this element, at the relative concentrations found, could only be formed as a result of a star going supernova over about 5 billion years ago. (I am probably off a little on the date). This meant that our sun had to have at it’s core the remnants of a super nova since it is the only star close enough to eject this kind of material. He subsequently checked data from NASA’s Galileo probe for strange xenon on Jupiter and sure enough he found it there. He had no theoretical bias as to how the universe formed; he just looked at the elements there and concluded that there had to be a nuclear fusion explosion. (Such an element would not be found in the traditional model in which the solar system formed from the collapse of a hydrogen cloud.)

He also points to the evidence indicated by the high iron content of the cores of planets. If our sun formed only from a gas cloud, then it would be anticipated that the heaviest elements would have sifted towards the center sun billions of years ago. If our sun exploded, it would have ejected some of the heavy elements out, which became the cores of the planets. The reason the material did not flow directly back into the sun after the nova is that our star must have had a very high rate of rotation. Also if there is significant material already around orbiting the sun, it would impart it’s angular momentum to the gathered ejected material.

It would be interesting to see if someone familiar with stellar physics tried to model a stellar structure with an iron core with an H - He atmosphere above an Iron core which produced the observed level of neutrino production.

Evidence of Iron

Another possible indication of an Iron core for our Sun is the existence of an Iron core in our Earth and most of the Planets. If our solar system did not form from ejecta from a supernova but from the gaseous particles in space, it would be anticipated that a kind of sifting of elements should occur within galaxies and solar systems as matter coalesced in space. Heavier elements and structures should accumulate towards the center. If the Earth has a substantial iron core, so too should the sun but to an even greater degree.

An indication that such sifting exists even on a galactic scale is evidence by the two types of variable Cepheid stars observed in Galaxies. It is with some hesitancy this factor is presented as evidence since it is somewhat ambiguous. Type 1 Cepheid stars have a regular cycle and tend to be located in Spiral arms of galaxies near Population I stars, such as our sun. I suggest that these variable stars have some iron at their core to provide stability. Type 2 Cepheid stars are irregular variable stars that tend to be located at the outer boundary of galaxies, and at the core. The reason for their irregularity is that they lack a sufficient iron core and will have a tendency to oscillate apart. The ambiguous aspect of this example is the observed occurrence of Type 2 at the core of galaxies. If matter coalesced with the heaviest and largest clumps forming to the center, irregular Cepheid stars should be found at the edges but not at the core. The reason for this exception is because of the increased density of the gas fond at the core of galaxies. It allows the creation of some stars with a minimal amount of iron at their cores.

Gas Stars are unstable

It is argued that stars composed of mostly hydrogen that are formed at the beginning of the universe are extremely unstable and explode or nova due to a positive feed back process. As the pressure increases in a gaseous star due to the rapid influx of matter, the energy production increases, temperature increases, which then expands the core of the gaseous star. This expansion then shoves outwards the atmosphere above it. Once the atmosphere is moving outward from the core, there is a pressure decrease at the core. This then causes the rate of energy production at the core to decrease, which also tends to further decrease the pressure in the core. This loss of pressure within the star then allows the atmosphere of the star to fall back to the core. When the atmosphere finally falls back to the core, the pressure dramatically increases, so the rate of energy production is even greater than when the process originally started off at. This process cycles over and over with increasing intensity until the star novas (throws off the outer atmosphere). The process of a star throwing off its atmosphere increases the core pressure enough to begin the formation of heaver elements. If a star novas with some heaver elements within, the result is a type II supernova.

Iron (and neutron) cores

Iron cores are necessary for the stability of stars at the quasar stage of a galaxies development. The stability that an iron core provides is from the cores ability to absorb energy, damping the cycle that would normally lead to a nova. If the atmosphere starts to collapse on an iron core, the temperature is increased. The iron core can absorb this heat without the associated increase in energy output. It is also possible, at the right pressure, for some of the atoms of Iron or other heaver elements, to fuse with other elements forming radioactive nuclear matter, resulting in further absorption of energy. Also since the core retains heat, it tends to maintain at a constant temperature even if the atmosphere were to “bounce” off the core, decreasing the pressure. Just as the Iron core absorbs heat, it also can release the heat if the atmosphere were to expand above the core. This constant heat source stabilizes the stellar core, preventing novas from occurring. Most stable stars in the universe in this theory are therefore composed of iron; it is the only way stability can be established, (my opinion).

Are present modeling methods accurate?

There is a tendency to think the status quo is right, particularly if the existing models of stellar evolution have been around for a while. It should be pointed out that present theoretical determinations of the structure of our sun are based upon a process called numerical integration, and numerical iteration, which is based upon guesses as to the interior structure of our sun and repeated adjustments are made in order to maintain stability.(“This layer must be this thick in order to….. etc.) There are more than a few graduate students who have chaffed at the assumptions necessary to account for stellar stability. I used to know of one student who no matter how he worked the numbers concluded that stars should blow up. None of these techniques, I think, adequately transfers to a simple and consistent basis describing energy production from stars, particularly when applied to variable stars.

The next posting will be called quasars and supernova fires and it will provide a model for the production of iron and neutron cores in quantities sufficient to resolve one of the issues mentioned by the BA.

(A brief aside. A couple of years ago I contacted the American Astronomical Society about presenting a paper on the uniform expansion of space. I could not get a sponsor, but when I stated over the phone that I predicted that most stars have to have iron cores for stability, I did get some interest. Now I know why, Professor Manuel was already registered at the conference to present a paper stating that our sun had an iron core).

Snowflake.

If he's basing much of his argument on the solar neutrino problem then he's definitely wrong. The "problem" has been resolved in the last two years via exactly the mechanism the BA suggests here. The Sudbury Neutrino Observatory measured the total neutrino flux from the sun. This included all three flavors. The total flux was nicely in line with the predictions of the standard solar models.

__________________
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." - William Thompson, 1st Baron Lord Kelvin

"If it was so, it might be, and if it were so, it would be, but as it isn't, it ain't. That's logic!" - Tweedledee

This isn't right. This isn't even wrong. - Wolfgang Pauli

Let me add my two cents regarding the evidence provided by helioseismology.

Go to GONG's website on helioseismology, and learn what these oscillations can tell us about the interior of the Sun. Here is a quote:

"Helioseismology utilizes waves that propagate throughout the Sun to measure, for the first time, the invisible internal structure and dynamics of a star. There are millions of distinct, resonating, sound waves, seen by the doppler shifting of light emitted at the Sun's surface. The periods of these waves depend on their propagation speeds and the depths of their resonant cavities, and the large number of resonant modes, with different cavities, allows us to construct extremely narrow probes of the temperature, chemical composition, and motions from just below the surface down to the very core of the Sun."

I'd have to dig for the reference, but I've read that they've been able to detect the sudden drop in the hydrogen abundance and rise in the helium abundance with the transition into the solar fusion core. All of this is just nonsense --- unless Dr. Manuel can provide a theory for the interior structure (and energy generation) that matches those inferred from the helioseismology and neutrino measurements to fractions of 1%, as is currently the case for the standard solar model.

I'll second the quote from Wolfgang Pauli, quoted just above me.

Hi Spaceman Spiff

Some of the current research about our sun is beginning to show, based upon the study that Helioseismology, that the sun has an interior of iron. How much is a matter of debate, but the research indicates that a core of hydrogen is clearly wrong. If you wish to check this out yourself

Title - Seismic Test of Solar Model, Soplar Neutriono and Implication for Metal-rich Accretion
Authors - Winnick,R.A Demarque,p Basu,S
Affiliation - Department of Astronomy, Yale university,
Journal, - the Astrophysical Journal, Volume 576, Issue 2 pp 1075 1084

This is a copy of the abstract
Abstract
The Sun is believed to have been the recipient of a substantial amount of metal-rich material over the course of its evolution, particularly in the early stages of the solar system. With a long diffusion timescale, the majority of this accreted matter should still exist in the solar convection zone, enhancing its observed surface abundance, and implying a lower abundance core. While helioseismology rules out solar models with near-zero metallicity cores, some solar models with enhanced metallicity in the convection zone might be viable, as small perturbations to the standard model. Because of the reduced interior opacity and core temperature, the neutrino flux predicted for such models is lower than that predicted by the standard solar model. This paper examines how compatible inhomogeneous solar models of this kind are with the observed low and intermediate degree p-mode oscillation data, and with the solar neutrino data from the Sudbury Neutrino Observatory Collaboration. We set an upper limit on how much metal-rich accretion took place during the early evolution of the Sun at ~2 M⊕ of iron (or ~40 M⊕ of meteoric material).

While this abstract relates primarily to iron within the convection zone, it does state that “selioseismology rules out solar models with near-zero metallicity cores” Our sun has a metal core, how big it is, is a matter of discussion.
Snowflake.

snowflakeuniverse, I believe you are severely misunderstanding that article. By "metals", astronomers mean anything heavier than hydrogen and helium. That includes oxygen, calcium, magnesium, etc. and not metals the way laymen think of them.

So a zero-metallicity core means just H and He, with no Ca, Si, S, Mg, etc. It does not mean metal like iron.

When they say it is over-abundant, they also don't mean there is a vast amount of metals in the core. They mean it has more than what is usually considered to be normal. Normal can mean as little as one atom per 100,000 being a metal.

There is no evidence whatsoever that I have seen indicating an iron core in the Sun, and a vast amount of evidence (which I have posted in other threads) that the core is not a big ball of iron.

Let me add a few more cents (sense) to what the BA said.

First, advanced models of the Sun now include the effects of heavy element differentiation (diffusion) over time. Heavier elements have some tendancy to drift toward the center of the Sun over long periods of time, though the Sun's convection zone keeps things well-mixed in its upper layers. Second, 40 Earth masses of meteoric material as an upper limit to the amount of heavy element accretion? The Sun's heavy element content is approximately 2% by mass, 40 Earth masses is just 1.2x10^-4 of the Sun's total mass, or about 0.5% the mass of the present convective envelope. Astronomers should and will continue to "punch at" the standard solar model, and this is a good jab but it looks to be a small brush at best. In any case, this has no bearing on the "iron core" idea, in fact if it has any relevance at all, this paper suggests that the Sun's convective envelope might have been enriched in the heavier elements (by this small amount), and that the deeper interior of the Sun has fewer of the heavy elements that had been presumed (even with diffusion), with a slight excess just beneath the convective boundary. However, the authors conclude that their best non-standard model does not match the helioseismology data as well as those of the standard model.

Finally, here is a paper that uses helioseismology to set an upper limit to the heavy element abundance in the Sun's core.