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The Sun Had Sisters
[TheBORG] writes to mention a Space.com article about the Sun's departed solar siblings. Our own medium-sized yellow star was far from alone when it was formed, with hundreds of fellow solar bodies and a supernova to keep it company. From the article: "The evidence for the solar sisters was found in daughters--such as decayed particles from radioactive isotopes of iron--trapped in meteorites, which can be studied as fossil remnants of the early solar system. These daughter species allowed Looney and his colleagues to discern that a supernova with the mass of about 20 suns exploded relatively near the early Sun when it formed 4.6 billion years ago; and where there are supernovas or any massive star, you also see hundreds to thousands of sun-like stars, he said. The cluster of thousands of stars dispersed billions of years ago due to a lack of gravitational pull, Looney said, leaving the sisters 'lost in space' and our Sun looking like an only child ever since, he said."
A finding like this would lend support to the Nemesis theory. If our sun and any of those sister stars are still in some gravitational cycle, it could help explain the periodic extinctions that seem to occur every 26 million years.
type II supernovas take an awful long time to mature
I'm pretty sure that's not true. Remember: the larger the star, the shorter its life. Really large stars have lifetimes of just a few tens of millions of years, while red dwarfs can live trillions, according to current theory. While a 20 solar mass star isn't that big, I imagine it still didn't last long.
Sit, Ubuntu, sit. Good dog.
I'm working on covering this for the Museum of Science, Boston on our podcast. I tracked down a PDF of the actual paper, if anyone is interested.