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To: decimon
Hm. Iron in a star is quite significant. No atom heavier than iron can be formed by a fusion reaction that releases energy. Forming any atom bigger than that requires a net consumption of energy. So when a star first starts it's fusion reactions, hydrogen fuses to form helium. Various reactions go from there to fuse atoms into heavier and heavier elements. The heat and radiation from these reactions expands the size of the star and keeps it going. But as the reactions form heavier and heavier elements, each reaction releases less energy than the last.

Eventually the star, filled with iron, stops runnning sufficient fusion reactions to keep it expanded. It then collapses. The jump in pressure kicks off fusion reactions that cause an explosion, a supernova. Atoms heavier than iron are formed in that explosion (lots of energy for a short time, no need to be self-sustaining) and scattered about. Eventually those heavy elements (to an astronomer, "metal" = any element heavier than hydrogen) condense into lumps that may in turn coalesce into planets.

Joni Mitchell and Carl Sagan were right - we all are made of star dust.

You're bound to see some iron in lots of stars, but you don't want to see a lot in the one you're orbiting.

6 posted on 01/04/2010 2:19:55 PM PST by RonF
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To: RonF

so in non-astrologer terms, is this showing the star we’re orbiting to contain some iron or a lot?


7 posted on 01/04/2010 2:58:11 PM PST by mentor2k
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