Long ago (4.6 billion years, to be exact), a hyper-advanced alien civilization had created a solar system from scratch. Somehow, they had artificially prolonged the center of the solar system--a stellar binary--to last trillions of years, as long as red dwarves. But the combined mass and luminosity of the two stars indicates that neither one is a red dwarf. As a matter of fact, the combined stars are so massive and so bright that:

  • The inner boundary of the habitable zone (the zone in which surface liquid water is possible) is 29 AUs from the two stars (29 times the distance from the sun to Earth) and any planet on that line with a rotation period of 36 hours would have an orbital period of 400 of these "days".
  • The outer boundary of the habitable zone is roughly 152 AUs from the two stars and any planet on that line with a rotation period of 36 hours would have an orbital period of 728 of these "days".

So using the specified information above, what kinds of stars would the mystery binary be?

  • 4
    $\begingroup$ A certain doctor Kepler observes that $\sqrt{(152/29)^3}$ is just about 12; or, 400 * 12 is 4800 rather than 728 -- and conversely, 728 / 12 is about 61 rather than 400. (Because the square of the orbital period is proportional with the cube of the semimajor axis.) Given that the stars exist in a universe where they have completely alien physics, the only answer is that they are, obviously, wondrously magical stars. $\endgroup$
    – AlexP
    Oct 15, 2021 at 22:15
  • $\begingroup$ I'm with @AlexP, you have manufactured stars and want to know what their classification would be as if they were natural. That's kinda odd. They obviously exist in your universe and the classificaton would have been created by the very same creators. So... you tell us, what kind of stars are your mystery stars? (Said another way, what's the problem you're trying to solve, because identifying stars that violate known classifications by definition doesn't seem to be a worldbuilding problem. It feels like a storybuilding problem.) $\endgroup$
    – JBH
    Oct 16, 2021 at 2:20
  • $\begingroup$ Science-Based and Science-Fiction tags shouldn't be used together and have no meaning together $\endgroup$
    – Or4ng3h4t
    Jun 21, 2023 at 11:01
  • $\begingroup$ To create solar systems that make sense, you need to read a few introductory books on astronomy and physics, and learn how to do simple calculations using Newtonian gravity and Kepler's laws. This isn't hard math, but you do need to be able to use a calculator and put numbers into formulae correctly. The alternative is to give up on specifying numbers for anything, a la Star Wars. Giving precise numbers that are inconsistent is the worst way to write SF, and just attracts mockery and derision. $\endgroup$ Jan 11 at 20:50

1 Answer 1


Director, the reports came back from the lab. This binary systems is truly strange indeed. Knowing that an object in a 14400-hour orbit (36 hours/day * 400 days/year) lies a mere 30 AU away from the binary pair, our best models predict that the combined mass of the pair is upwards of ten thousand solar masses. This, in combination with the extremely stable lives of the stars and the higher luminosity of the stars, leads us to believe that they are in fact artificial, and that they may actually be powered by strangelets.

Yes, those are real calculations: given a 14400-hour orbit for a relatively small body (I assumed about 1 Earth mass) around this pair, the mass must be around 10,000 solar masses. But they’re also burning hard, and for a long time: a trillion years far exceeds the lifetime of our Sun, let alone a binary pair ten thousand times as massive. So what reaction is powering these fireballs?

The answer is actually the weak interaction: in the cores of the stars lie barely-stable strangelets, where matter comes into contact with the surface of the strange-matter glob, converting the hydrogen, helium, and CNO elements in the star into strange matter. Then, because the strangelets is just slightly unstable, the outermost layer of the strangelets “burn off”, with the weak interaction converting the strange matter into regular matter. Quickly, the raw quarks produced would assemble themselves into the simplest possible element: hydrogen.

Essentially, the strangelets are acting like a recycling plant for the stars. They take the fused helium fuel and convert it back into hydrogen, and if the masses of the strangelets are very carefully selected (which I assume your ancient aliens are capable of), then they will keep working for trillions of years until they either go subcritical and disintegrate as they become increasingly unstable or supercritical and become more stable as they consume the entire mass of the star.

Strangelets are awesome, and you can find more info on Wikipedia. Essentially, they are made of matter that’s composed of strange and charm quarks rather than up and down quarks, and it’s possible (assumed true in my explanation for your magic binary stars) that a larger strangelet is more stable than a small one, meaning that matter it comes in contact with would be “absorbed” and converted into strange matter before the strangelet decays back into regular matter.


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