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In a world I'm currently building, I've devised a magical creature that sustains, indefinitely, a Class O hypergiant star. This, of course, violates conservation of mass and conservation of energy.

Class O hypergiants tend to detonate in short order (in astronomical terms), but they produce the heaviest elements that occur naturally in the universe. If such a star could be sustained by my creature, what would happen to the star in the long term?

Would it continually smash together increasingly dense atoms to form an increasingly dense core? If this happened long enough, would the star collapse into a black hole?

Finally, what mechanism do I need to give my creature to prevent its presence from unintentionally destroying the star it preserves, if such a stellar fate is determined?

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    $\begingroup$ Is your answer not "magic?" If you're violating the conservation of mass and energy to sustain your hypergiant indefinitely... you can really make the star do absolutely whatever you please. The heavier atoms will do whatever your magic makes them do to "sustain the star indefinitely." (You might be able to eek a science based answer out with some careful craftsmanship of what "sustain" means) $\endgroup$
    – Cort Ammon
    Aug 17, 2015 at 19:58
  • $\begingroup$ @CortAmmon I was trying to get an understanding of what natural impacts would be incurred from this arrangement but, yes, I could have the creature foster the star and intelligently control what goes on within the core. Hence my use of "sustain" and "maintain." $\endgroup$
    – Frostfyre
    Aug 17, 2015 at 20:48
  • $\begingroup$ The trick that allows star to work is that when elements fused they produce light and light emits pressure to oppose the gravitational pull on all materials inside the star. The problem arise when that pressure can no longer combat gravitational force due to decline in amount of light produced, btw when light is produced in a fusion process it took million of years to reach the surface of the star. $\endgroup$
    – user6760
    Aug 18, 2015 at 1:49

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Actually, the heaviest elements are created during the "detonation". That is, by supernova nucleosynthesis rather than stellar nucleosynthesis. Stuff heavier than iron came from the death of stars, their supernova. As Lawrence Krauss put it:

So, forget Jesus. The stars died so that you could be here today.

To your questions:

If such a star could be sustained by my creature, what would happen to the star in the long term?

It, by definition, would be maintained by magic. As for maintenance, the creature would need to clear the iron out of the core occasionally.

Would it continually smash together increasingly dense atoms to form an increasingly dense core? If this happened long enough, would the star collapse into a black hole?

It would smash together atoms up to the density of iron. It would not collapse into a black hole unless more mass was added. Increasing density without losing mass just means the star would get smaller in volume, not more massive.

Finally, what mechanism do I need to give my creature to prevent its presence from unintentionally destroying the star it preserves, if such a stellar fate is determined?

It needs not to be massive enough to cause the star to collapse into a black hole. It's incredibly difficult to mess with stars, unless it's done with other stars. Any creature, especially one using magic to maintain the star, would easily avoid accidentally destroying the star. For instance, I avoid harming the Sun every day without much effort.

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  • $\begingroup$ From the shows like How the Universe Works I knew iron was the death knell for stars and heavier elements followed, but I thought the star was still alive (albeit briefly) during their formation. If my creature were inserted into the picture during the downward spiral, could the star be maintained on the edge of supernova and produce the heavier elements? $\endgroup$
    – Frostfyre
    Aug 17, 2015 at 20:50
  • $\begingroup$ @Frostfyre No, not in any feasible sense. You'll have to resort to full on magic hand waving for that. I would word it exactly as you have, maintained on the cusp of supernova. This would be a bit like the Restaurant at the End of the Universe, rocking back and forth in time across the supernova detonation point. $\endgroup$
    – Samuel
    Aug 17, 2015 at 21:00
  • $\begingroup$ If the magical creature can save the star, by flushing iron and adding H to balance the mass, presumably it could use the internal conditions to fuse heavy atoms to the post-iron elements. Seems like a lot of work when magic was supposed to turn lead to gold without a star at all. $\endgroup$
    – Oldcat
    Aug 17, 2015 at 21:32
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    $\begingroup$ Iron fusion is possible, it simply requires energy input. Perhaps if the creature did that, it would be easier than removing material, which would also cause instabilities in the star. $\endgroup$
    – HDE 226868 ♦
    Aug 17, 2015 at 21:51
  • $\begingroup$ "For instance, I avoid harming the Sun every day without much effort." [citation needed] $\endgroup$
    – LindaJeanne
    Feb 22, 2016 at 14:47
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Your creature would need to do two things to maintain the star.

The first is to clean out the heavier elements as they are appearing. It may be enough to just focus on Iron (the final end result of fusion) but probably safer to start cleaning things out considerably sooner.

The second is to constantly supply more hydrogen throughout the star.

Think of it as the difference between a wood fire and a gas one. In a wood fire you put the wood in, set light to it. The wood burns away and leaves ash behind. In a gas fire there is a constant supply of gas and oxygen coming in, this burns and the result drifts away.

Your creature needs to convert the star from burning like the wooden fire to like the gas fire.

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Maybe your creature is multi-dimensional and it is in several locations at once, one constantly feeds new fuel into the O-hyper giant, and another section removes the heavy elements to a 3rd location where it 'needs' or uses them. Maybe the creature was designed just to 'grow' and 'harvest' heavier elements for the use of others (maybe long since gone and forgotten?)

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  • $\begingroup$ This only addresses the creature-mechanism portion of my question. $\endgroup$
    – Frostfyre
    Aug 17, 2015 at 19:55
  • $\begingroup$ I guess, I assumed that if it was bringing in the same mass of fuel that it is removing in finished 'product', the star will be eternal because it won't get too massive and it won't run out of fuel.. $\endgroup$
    – bowlturner
    Aug 17, 2015 at 19:59

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