Re: A trinary system (G/M+A)

Thinking about this a bit more.

1) Stars lose a lot of mass -- like, half or more -- as they move
from main sequence through red gianthood to white dwarves. Some of
this is blown away as solar wind; some goes into the planetary nebula.

This means that, over geological time, the pair will drift further
away from the evolving A star.

Of course, the pair is so distant that the revolution around the A
takes thousands of years anyhow. Still, if the alien race is keeping /
meticulous/ records for tens of millions of years, they'll notice.

2) At a range of ~~140 au, I don't /think/ a planetary nebula will
have much impact on the pair or their planets. Still, might be worth
doublechecking. Of two binary systems nearby with white dwarf
companions (Sirius and Procyon), both show enhanced metallicity in the
main sequence survivor and one -- Sirius -- is oddly dusty. (Odd
because Sirius B settled down to dwarfhood ~100 million years ago, and
the dust should have settled by now.)

3) Planetary nebulae are frickin' huge, 100s of au across. So the
pair will be inside the nebula. I think you can still fudge the
"crown" thing, but FYI.


Doug M.

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