I was wondering...

Assuming someone or something were to remove all the hydrogen and helium from the sun, that the remaining elements cooled and did not immediately fly off into space, what would be left?

Would the remaining elements coallese into some kind of planet like body? Would it be largely metallic or would oxygen and other elements become bound to the metals leaving us something more rocky? Would it form an atmosphere?

I've looked around on the net and there's plenty of info on the suns composition. The remaining ball would be less then 1% of the suns orininal mass and without hydrogen there wouldn't be any water or other hydrogen based compounds, so my guess would be that it would end up as a huge great ginormous (scientific term :wink: ) rock.

Or am I over simplifying this?

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Based on this info from the Nine Planets website, most of the remaining mass would be primarily oxygen (47%), carbon (17%), neon (10%) and iron (8%). 1-3% each of sulphur, silicon, nitrogen and magnesium.

If all you did was magically remove the H and He, then the remaining elements would still be darn hot, and would continue to radiate for a good while -- I suppose this isn't much different than a white dwarf?

If, as you postulate, everything cooled also, then presumably the remaining elements would eventually coallesce into a rock. There would be some gravitational heating, but eventually the elements would react to form oxides of carbon, nitrogen etc ---- presumably with a neon atmosphere until the rock cooled enough to condense neon.

Meanwhile all of the planets would fly off on parabolic orbits. Some of the orbits would likely cross, so eventually there would be interactions and eventual collisions.

Thanks.

I kinda figured the planets wouldn't hang around long if 99% of the suns mass suddenly disappeared

Always nice to know when a pretty wild idea turns out to be about right. I was discussing this with a friend and he was sure it would turn out to be something more exotic.

The way I see it, assuming that the suns mass is approx 2 × 10^30kg then the remaining rock would be 2 × 10^28 kg.

I make that about 3000 times more massive than the earth.

That's a big rock.

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God: I refuse to prove that I exist. For proof denies faith and without faith I am nothing.
Man: But the Babel Fish is a dead giveaway isn't it? It proves you exist and so therefore you don't. Q.E.D.

Except for not being, you know, electron-degenerate.

Wait a minute;
it sounds to me like you would end up with a ball which was mostly oxygen and carbon dioxide, with a relatively small heavy ball of impure sulphur - rich rust at the middle.
Not really a rocky ball at all.

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Wouldn't it all be mixed together - a collection of metal oxides and other compounds? Or are you suggesting the relative densities of the elements would create a layered effect?

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God: I refuse to prove that I exist. For proof denies faith and without faith I am nothing.
Man: But the Babel Fish is a dead giveaway isn't it? It proves you exist and so therefore you don't. Q.E.D.

Well, about half of the oxygen would combine with all the carbon to create carbon dioxide; about another tenth would combine with the iron and other elements- that leaves 22% free oxygen or thereabouts. A oxygen/CO2 gas giant 10 times as massive as Jupiter.

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No, I'm wrong;
the carbon atoms each absorb two oxygen atoms, and of course many of the other oxides contain multiple oxygens as well; there would be little or no free oxygen left after all that, so the atmosphere of this gas giant would be mostly CO2 (and neon)after all.

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True, but I don't think it would stay a gas giant all that long, the CO2 would solidify once it got cold enough as would the neon.

That would presumably leave a huge lump of dry ice / neon ice with a dirty great big rocky core.

What the heck would that be classified as?

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God: I refuse to prove that I exist. For proof denies faith and without faith I am nothing.
Man: But the Babel Fish is a dead giveaway isn't it? It proves you exist and so therefore you don't. Q.E.D.

Yes. 1 kg of carbon combines with 2 and 2/3 kg of oxygen, so 17 mass units of C use up 45-46 mass units of O - carbon alone would use up almost all oxygen in the Sun. Iron would be more thsn enough to absorb the remainder; no free O2 at all.

Overall, you would get a mostly CO2 gas giant with an iron-sulfur-magnesium core and an admixture of neon.

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Hmmm, you may be right there. Without a star nearby to provide energy I'm not sure if this Sun-planet would radiate enough heat to keep the CO2 from solidifying. It should still have a hot interior, much like the other inner planets, but would that be enough? :-k

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