# How to Construct a Stellar Instar

In real science, an "instar" is simply a developmental stage between molts in arthropods. But in fictional science, it is an artificially constructed structure that is designed to function like an actual star. Here's the twist--an instar is designed to be all types of main-sequence stars in one same body. Like with the arthropods, the instar "molts" into different types depending on age. Here is the list of developmental stages, from youngest to oldest:

1. O stage: 100 times as massive, 19 as wide and 810,000 as bright as our sun; 440,000 years
2. B stage: 18 times as massive, nine as wide and 180,000 as bright as our sun; 72 million years
3. A stage: Three times as massive, 2.7 as wide and 80 as bright as our sun; 1.4 billion years
4. F stage: 175% as massive, 182% as wide and 8.5 times as bright as our sun; 5.2 billion years
5. G stage: 110% as massive, 105% as wide and 126% as bright as our sun; 14 billion years
6. K stage: 78% as massive, 85% as wide and 40% as bright as our sun: 52 billion years
7. M stage: 60% as massive, 51% as wide and 7% as bright as our sun: 1.2 trillion years

So that's seven stellar molts totaling up to a lifespan of 1,272,672,440,000 years. But if this were artificial, then that means that technology is needed to make sure that this star gets its seven separate molts without intervention (as in once it's initially completed, it's left to fend and do its seven molts all by itself.) How can this be accomplished?

• Can you clarify your question? I assume you're not looking for a patentable design. What kind of information are you expecting in a best answer?
– JBH
Commented Jul 16 at 5:42

Your "O" stage construct contains enough material for 5.5 "B" stage constructs, each of which contains enough material for 6 "A" stage constructs. Assuming the problem of initially gathering it is solved by just starting with an O-type hypergiant, that mass isn't going to just disappear. A lot of it will be blown off as the hypergiant ages, but converting it into a young B-type main sequence star is going to involve entirely dismantling an unstable O-type star at the end of its life to remove its core and stop helium burning before it explodes. Then, use the remaining hydrogen to build a new B-type star...perhaps the stellar wind can be captured and stored (in the form of more red dwarfs?) until needed. Your "instar" is just a vast collection of machines for dismantling and rebuilding stars.

But...why? The progression implies the ability at any time to just build hundreds of smaller, longer-lived stars of whatever you consider the ideal size to be, or whatever suits your immediate needs, without waiting billions of years. Why wouldn't the creators of the required machinery just do that instead? The ability to create one of these "instars" implies capabilities that make it completely unnecessary to actually do so.

I would suggest that the easiest route is to start with a natural O-Type Star blue star, although technically at 100 Solar masses the O stage is bigger than any main sequence star we know of. Then use star lifting, in which electromagnetic fields are used to strip hydrogen, and sometimes heavier elements, from the outer atmosphere of the star, to steadily bring the mass down as time goes on. You can even store the hydrogen, use it for fusion, or, in theory, to extend the later, full convection, K and M phases.

What happens to the extra mass?

Your Instar keeps getting smaller far faster than it could ever do on its own, no matter how well designed.

The only solution i can think of, is that the Instar experiences a "fly by" of a rogue star, that manages to pass it by close enough to starlift a good portion of the Instar's atmosphere and go run away with it (possibly creating some planets from the cast-off?)

Any other solution we could use to lift this much mass would require near constant work, supervision and infrastructure, basically a near permanent Dyson Sphere.

It would be easier to answer this question if we knew what the Instar is build for. As of now, it is hard to come up with a solution that would not take more time, energy and effort than a functional Instar would provide.

• Nah artificial star lifting only really needs an equatorial band of statites.
– Ash
Commented Jul 16 at 7:16
• It's for a seedworld project. Commented Jul 16 at 14:21
• @JohnWDailey what exactly does that mean? What is a "seedworld" and how does going through a series of high-mass short-lived stars benefit it? Commented Jul 16 at 22:00
• A seedworld is a speculative evolution subtrope in which Earth organisms are slated to colonize an extraterrestrial world and left to allow evolution to take course unabated. Commented Jul 17 at 0:30
• @JohnWDailey and what does that have to do with repeatedly rebuilding a star? What do you gain from wiping the slate clean and throwing away 82% of your starting mass after less than half a million years, and then doing that again and again with smaller stars? If you wanted to "allow evolution to take course unabated" you'd just build a decently long-lived star with a useful habitable zone. Commented Jul 17 at 21:53