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[T]his coincidence enabled stars in the late stages of their lives to turn helium into carbon, oxygen and most of the other atoms that you and I are made of. [...] [W]e're made of star stuff.

Max Tegmark, Our Mathematical Universe: My Quest for the Ultimate Nature of Reality, p. 64

Assuming that the Sun is not in the late stages of its life, I read that as that we are made mostly of star dust, but not Sun dust. Rather, we apparently are mostly made of atoms produced by earlier (now dead and buried) stars.

My question is whether it is likely that there was one immidiate (o.a. carbon-producing) predecessor star to the Solar System, or whether the Solar system likely has more than one (perhaps many) (o.a. carbon-producing) "parent stars"? (And, there seems to be also also a third "possibility": that the build-up of, say, carbon takes more than one generation of stars.) What's the (hi)story here?

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Great question! Stellar history is a really interesting area to dig into. –  called2voyage Jan 13 '14 at 14:31
Vaguely related on Physics:… –  dmckee Jan 14 '14 at 2:38

3 Answers 3

The precise presolar history isn't known. I'll try to tell a likely story backward in time.

Our sun probably has brothers and sisters scattered throughout the Milky Way. Further back in time our sun likely was part of on open star cluster like the Hyades. Open star clusters are not stable and eject stars over hundreds of millions of years. (More about attempts to find Sun's siblings.)

Such star clusters typically form in nebulae like the Orion Nebula. Dense nebulae typically contain short-lived stars with multiple solar masses, which typically end as supernova, adding heavy atoms to the nebula and surrounding interstellar medium. Our sun is rich in heavy atoms, easy to detect in spectral lines of sunlight or in solar wind; those atoms cannot have formed in the sun, because its core is not yet hot enough to form these elements; some will never form in the sun. Earth mainly consists of chemical elements heavier than helium. Stars like our sun, rich in heavy elements, are called population I stars (astronomers call all chemical elements besides hydrogen and helium metals). Population I stars (and Earth) can only have formed, at least in parts, from supernova remnants. Old stars, born in a time, when the immediate predecessor(s) of our sun were born, can still be found in the Milky Way. They are called population II stars. They contain less material made of heavy elements than our sun, but still more than provided by the big bang. Therefore there must have existed even older stars, called population III stars.

Supernovae also can destabilize the interstellar medium due to shock fronts, eventually leading to local collapse especially of nebulae.

Presolar grains are still raining down on Earth; "the elements in these particles were made at different times (and places) in the early Milky Way".

By this, the likely answer to the question is, that we probably consist of remnants of several supernovae, and of several generations of supernovae.

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+1 Thanks, this is a clear answer. About "opinion": Is this an opinion shared by most of the specialists? Is it mainstream consensus? The typical working hypothesis? Etc. (Could you include something on that in your answer?) –  Glen The Udderboat Jan 12 '14 at 19:54
Nice answer. Would be cool to work Metallicity of stars (i.e. - pop I, II, and III) stars into your answer. –  astromax Jan 12 '14 at 19:58
@GlenTheUdderboat Tried to stay as close as I could to the current prevailing pov. –  Gerald Jan 12 '14 at 23:32

It is highly unlikely that we're made out of stuff from only one star. The simplest reason for this, is that we have gold on earth. Gold is (we believe) created by the collision of two massive stars (neutron stars probably).

If there was only one predecessor to the sun, it would be extremely likely that all of its mass would still be nearby. The total mass of the entire solar system is much to small to have formed for example nickel and copper in any noticable amount. You would have to have a star of about 5 times the mass of the solar system. That mass doesn't go away.

You could, of course speculate that a couple of neutron stars at 2-3 times the solar system initially created everything, then split up into around 2-3 different solar systems. But we have quite a lot of chemical elements such as hydrogen and helium in the sun, which there would not be a lot of in neutron stars (due to it having to have fused into heavier elements).

All stars go through a few stages from their inception to their death:

Initially, the theory is that hydrogen was the prevalent chemical element. It's the "simplest" chemical element. When helium is compressed, due to the gravity of a star it's temperature will rise up. Once it reaches around 10 million degrees, fusion starts. Fusion of hydrogen creates helium.

Helium, being heavier than hydrogen will sink to the center of the star. Later, you will have helium fusion, if the star is massive enough to compress helium enough. Helium will generate oxygen and carbon.

A very massive star, multiple suns in mass, is able to fuse oxygen and carbon - which creates a lot of different chemical elements; neon, sodium, magnesium, sulfur and silicon. Later reactions transform these elements into calcium, iron, nickel, chromium, copper and others.

Eventually, many stars will explode into a supernova. In that process, a lot of these materials will be ejected into space, where they will gather due to gravity again.

The sun was probably created in a messy universe, where hydrogen and perhaps helium came together in a region where there was a lot of these other chemical elements.


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Your argument is really confused. You've said that because we have gold on Earth this must mean that we cannot be the product of a single star. While I agree that we almost certainly are created from the bi-products of many stars in the galaxy, your logic is flawed. You then proceed to explain basic stellar astrophysics (without any mention of sources whatsoever), which is not what the OP is asking for. Also, what is "eon" ?? –  astromax Jan 15 '14 at 0:34
I've corrected the article; neon, not eon. I also think that explaining why it is unlikely that we'd get much of both for example helium and gold from a single star is helpful, even though he didn't ask. There won't be much helium left in a gold producing star. Also it's been observed that neutron star collisions create gold and could amount to all the gold in the universe: –  frodeborli Jan 15 '14 at 8:15
That is an incorrect argument. Supernovae produce gold. Also, what evidence do you have to support that "there won't be much helium left in a gold producing star". I'm calling you out - I am now convinced that you are making up nearly everything you have said on this site. –  astromax Jan 15 '14 at 15:26
I'm really sorry if this comes off as an attack, but you're doing more harm than good by answering in this fashion (that is, with no proof of what you're claiming, and additionally, nearly always incorrect in some sense). –  astromax Jan 15 '14 at 15:27
@called2voyage Duly noted. My bad - I got a bit over-zealous with this particular answer. frodeborli, yes, I have read that paper. My problem is twofold: 1) You should always cite, even if it's common knowledge in the astronomical community. Your example of common knowledge is in fact demonstrably NOT common since, it has not been conclusively shown to be the only cause of gold production in the unvierse. Additionally, it makes your answer better! 2) The other issue I had was that some of your explanations are really poor (not just on this answer, mind you). –  astromax Jan 15 '14 at 18:36

The short answer is: we are made from the "stuff" contributed by many stars. The interstellar medium from which the Solar system formed was enriched by all sorts of elements synthesised in previous generations of stars. Most of the heavy elements are formed and injected into the ISM in a supernova explosion of a massive star.

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About half the heavy elements beyond iron are formed (by the s-process) and dispersed into the ISM (through mixing and winds) by AGB stars that do not end in a supernova explosion. –  Rob Jeffries Jun 8 at 9:56

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