

Age of stars is pinned to their spin - sjcsjc
http://www.bbc.co.uk/news/science-environment-30691779

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lucaspiller
> Astronomers use sun spots, travelling across the surface, and these only dim
> its brightness by much less than 1%.

How do they know they are sun spots and not a very small planets? I'd assume
planets have a more regular schedule, but unless you watch a star for years
(Julian), how can you tell?

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ars
Where does the angular momentum in a star go?

To orbiting planets? If so, I wonder if they can use that 10% error to infer
things about the planets orbiting that star.

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raverbashing
Good question, I wonder where their angular momentum comes in the first place

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derekp7
The same method that cause water in a drain to swirl. A star is a gravity
well, like a hole, where particles fall into. A randomly variable number of
particles are hitting each side -- the side that gets more particles sets the
spin in motion, which in turn gives influence to the rest of the particles
falling in, accelerating spin.

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civilian
It's also conservation of angular momentum--- a very slow spin that's spread
out will become much faster when it's pulled tightly in. You can watch ice
skaters do the same thing--- moving their limbs in or out to speed up or slow
down their rotation.

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exratione
There are a very few candidate population 3/population 2.5-ish stars that have
been discovered in past years, classification based on extremely low
metallicity. It would be interesting to see what the spin methodology has to
say about their ages.

