A young B-type star (with a mass of about 10 M$_{\odot}$) is surrounded by a debris disk extending from about 2 AU to 1000 AU away. The disk has a mass of about 300 Earth masses - enough to form quite a lot of planetesimals. There is also an outer cloud of icy, comet-like bodies extending from 750 AU to 5,000 AU away.

The star stands out from other Sun-like stars, though, because recently a strong stellar wind has developed, which comes with a mass loss rate of about 1.0 $\times$ 10^-6 M$_{\odot}$ per year. The stellar wind may die down eventually, but for now it's having quite a strong effect on the star and its disk. It is thought that much of the inner debris disk will be blown away very quickly.

A nearby red dwarf of about 0.76 M$_{\odot}$ (not a flare star, fortunately) is passing through. At its nearest point, it comes extremely close - an astounding 1500 AU away from the B-type star!

There will absolutely be some accretion by the red dwarf. But how much? An advanced civilization (Type II on the Kardashev scale) is watching closely. They're considering the red dwarf as a sort of "rest station". If planetesimals form, they could be mined for raw materials, and any icy bodies could be an excellent source of water - which can be turned into hydrogen and helium.

How can they figure out just how much dust from the debris disk and icy bodies will be captured by the red dwarf? Can they then predict if planetesimals are likely to form (though subsequent planetary formation isn't necessary)?

That bit could be construed as pure science, which it may be. But there's another, much more important question that's absolutely related to world building: Can the Type II civilization do anything to influence accretion?

posted almost 10 years ago

4y ago

HDE 226868‭

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