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New Class of Stars Are Totally Metal, Says Astrophysicist
KentuckyFC writes Stars form when clouds of gas and dust collapse under their own gravity, generating enough heat and pressure to fuse the atoms inside them together. When this cloud of dust and gas is the remnants of a supernova, it can contain all kinds of heavy elements in addition to primordial hydrogen, helium and lithium. Now one astrophysicist has calculated that a recently discovered phenomenon of turbulence, called preferential concentration, can profoundly alter star formation. He points out that turbulence is essentially vortices rotating on many scales of time and space. On certain scales, the inertial forces these eddies create can push heavy particles into the calmer space between the vortices, thereby increasing their concentration. In giant clouds of interstellar gas, this concentrates heavy elements, increasing their gravitational field, attracting more mass and so on. The result is the formation of a star that is made entirely of heavy elements rather than primordial ones. Astrophysicists call the amount of heavy elements in a star its "metallicity". Including preferential concentration in the standard model of star formation leads to the prediction that 1 in 10,000 stars should be totally metal. Now the race is on to find the first of this new class of entirely metal stars.
or Kerrang! They're full of metal stars
When did Nathan Explosion become an astrophysicist?
First metal star should be named after them.
Wow - a new low in poorly written summaries, sorry.
**bangs head**
Thank you Dave Raggett
Every time I hear about a (cool) new kind of star like this i get all teh happi feelz
It reminds me of the Cosmos where Sagan elucidates how everything and everyone we've ever known is made of "star stuff" & our composition reflects our star's composition
So...what kind of planets & planetoids would a **METAL STAR** make???
Thank you Dave Raggett
... they're called Class \m/ stars.
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That totally rocks!!!!
Let's take TFA at face value, and assume one in 10k stars start their evolution as count as "metallic" stars.
Hydrogen main sequence stars burn for a a few million years (for the class O supergiants) to literally trillions of years (for the class M all-but-failures). Helium burning, in a star with sufficient mass, lasts between a few hundred thousand to a few dozen million years.
The subject of TFA starts after helium burning normally finishes - Next on a typical star comes carbon, lasting for only a few hundred years; Then comes neon lasting for a single year, oxygen at half a year, and silicon finishes its run in a single day.
So whether or not a star begins life with a high concentration of trans-lithium metals, it will have a very, very short lifetime; That one-in-ten-thousand creation ratio therefore reduces to more like one-in-a-trillion among those stars still shining in our nighttime sky.
Err, no. None of that is true, and this news doesn't make it any truer.
systemd is Roko's Basilisk.
Stellar fusion can occur with atomic elements up to iron. There are a number of metals that are lighter than iron. If I'm reading this right, stellar fusion could conceivably be triggered by heavier metallic elements if they were "selected for" by the properties of vortices during the formation process.
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What astronomers mean for the word "metal" isn't what the rest of us mean.
As mentioned in the link to Metallicity, the all metal stars could be composed of carbon, nitrogen, oxygen, etc. Basically anything other than hydrogen and helium.
No, they really are not. Gravity has very little effect at the atomic level, but at the level of solar systems is the primary force.
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Doesn't seem that far fetched when you consider hydrogen is a metal....
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Now that's heavy metal I could actually get into...
Um.. but no energy could be released from such a star surely, since fusion of anything heavier than iron produces no energy, but actually takes energy. The only way it could produce energy then would be fission. But I'm skeptical about whether a star in such circumstances would really light up, or would just be a sphere of dead metal.
Additionally, in astrophysics the term "metal" includes many elements which are not metals in any other field. Astrophysically, metals are any element other than hydrogen or helium, so in addition to ordinary metals like sodium and lithium non-metallic elements such as carbon and oxygen are counted as metals.
To be clear, there are some varying definitions out there from anything other than hydrogen to anything other than hydrogen, helium, or lithium. Other than hydrogen and helium is the definition I've run across most often.
Let's not confuse extreme metallicity (the rare star containing nearly zero hydrogen or helium) with an all-metal body.
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Unless it's made of a light metal...then we'll name it Warrant.
My
If I'm reading TFA correctly, it basically means that stars formed from one molecular cloud have very different metallicities - anywhere between the mean metallicity of the molecular cloud and the "purely metal" extreme. If this is actually true, there may be far reaching implications for the research of stellar clusters. One of the basic assumptions in this field is that all cluster stars created from a given molecular cloud have very similar chemical compositions.
Cybertron
Helium is not!
If you read the article, however, it would point out that astronomers use a skewed definition of "metal", as any element heavier than lithium.
At birth, stars contain little helium, but is is constantly generated by fusing hydrogen.
If you start with metals like sodium and potassium, plus what we normally call non-metals, like carbon and oxygen, then you won't get around to generating helium until you fuze something radioactive that emits an alpha particle.
In astrophysics, the term "metal" normally applies to any element heavier than lithium. Carbon, silicon, even gasses like oxygen and nitrogen, are "metals". We're not talking about star remnants that are primarily iron or lead or uranium. Gold would be right out.
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And we have been studying stellar spectra for a century now. The must be much rarer than 1 in 10,000 or we would have already found one. They must be exceedingly rare.
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It's not a planet unless it's a planet. And if it's generating radiation through fusion, it's a star of some kind.
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so, i'm supposed to worry about 1337 h4xxxx0rz who have my public email, which I made public, right in my profile?
Thank you Dave Raggett
1. In astronomy all the elements except for Hydrogen and Helium are in the category "metals", so no.
2. In astronomy planets are things which orbit stars (plus some other criteria), so no.
The best part of which is that hydrogen is, technically, a metal! (It doesn't act like one in water-based chemistry, but it does in some other contexts.)
Hehe, astonomers, they're in their own world.
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No, they really are not. Gravity has very little effect at the atomic level, but at the level of solar systems is the primary force.
No, they might very well be. But it is just speculation --- accomplished science neither shows whether they are or not. It's just speculation, either way.
Iif you subscribe to the Bohr model of an atom... our solar systems are a larger scale universe's atoms, then the force we call "Gravity" could be the larger scale universe's electromagnetic force, and then Earth would be an "electron" orbiting the Sun, which would be our nucleus.
The laws of chemistry and physics applicable to the universe at the different scale would have to be quite different.... which is not to say that our solar systems are not another universe's fundamental particles.
2. Not entirely. There are planets without stars, and there are stars which orbit stars (well, stars which orbit a barycentre between itself and another star, which may or may not be inside the other star).
The Bohr model is not an accurate description of atoms, so it's pointless to try to compare anything to it and claim you are comparing to actual atoms.
My heart's an iron fist ... http://www.youtube.com/watch?v...
The iron doesn't "want" to come apart, and doesn't.
The star is a fine balance of gravitational attraction that compresses of all its parts to the point of fusion at the center, and the expansion of the star as the pressure of fusing energy at the center wants to expand the star.
At first, hydrogen is converted to helium and that process is so energy-rich that the star doesn't struggle much to hold off the collapsing effect of gravity.
As other elements are converted from one to the other, the fusion process is less efficient in producing energy and the star struggles even more to fight off gravity and becomes more dense
At the last stage of the star's life, when it produces iron, the star hits a brick wall. Fusion is not robust enough to convert iron into the next element.
What happens next is amazing because gravity finally overcomes the expanding process of fusion.
The star collapses very quickly, and THAT enormous pressure jams particles together so violently that heavier, more complex elements than iron are made through fission, and at the same time, the star is exploding.
The iron atoms do not come apart. They ride the shock wave.
It little behooves the best of us to comment on the rest of us.
Yep. Carbon, nitrogen, oxygen .. all metals. To an astrophysicist, we're not made of meat, we're made of metal.
(Okay, there's a fair bit of hydrogen in our mix, too.)
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You're thinking in terms of terrestrial temperatures. As gravity and friction do their thing as the elements clump together, the temperature rises -pardon the pun- astronomically.
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I expected the astrophysicist to be Queen guitarist Brian May...
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Huh? It's been demonstrated many times in many different ways that gravity is by far the weakest of the fundamental interactions. Gravity makes little difference at the atomic and subatomic levels. Atoms are not mini-solar systems. The forces that bind atomic nuclei and bind electrons to atomic nuclei are fundamentally different from gravity. Here's a tip; at least at the temperatures and densities you will find virtually everywhere in the universe today; gravity, electromagnetism, the strong and weak interactions are very different.
Christ pal, your claim was known to be rubbish eighty years ago. To see someone making a claim that atoms are mini solar systems in the 21st century isn't too far different from someone claiming the Sun orbits the Earth.
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It's crazy but my hearing is excellent at 48. That's after ~30+ years of blowing them out with Lemmy and other noise. I'm sure one day damage will just arise.
Trolling is a art,
Sure. And if you subscribed to the Ptolemaic model of the solar system, then I suppose you'd have some other theory of atoms.
To see someone making a claim that atoms are mini solar systems in the 21st century isn't too far different from someone claiming the Sun orbits the Earth.
You're either a nasty troll, or you just aren't paying attention at all. The claim was not that atoms are mini solar systems: quite the opposite; that our solar systems themselves are subatomic particles at a grander superscale: a superscale at which our entire solar system weighs something like 3 × 10^-29 grams. And the passage of time from our point of view is such that when we perceive 1 second of time passes, at the superscale, approximately 10^-29 seconds has elapsed.
Our "gravity" may be analogous at the superscale, to what we call the electromagnetic force. And at this larger scale, our stars would essentially be the core of the atomic unit, and the cloud of large rocks orbiting them would be analogous to electrons.
Since, the whole thing is that, our universe is essentially at a "quantum level" compared to whatever is happening at the "super scale"; we have no way of reasoning about what the laws of physics would be at the super scale. There may well be new forces and spatial dimensions emerging at the larger scale, analogous to our weak forces such as gravity.