THE Sun formed from the ashes of an earlier generation of stars that once
milled around near the centre of the Galaxy, an astronomer has claimed following
a study of meteorites.
Meteorites contain 鈥減resolar grains鈥濃�攕amples of the dust cloud that
formed the Sun. The grains are rich in silicon-29 and silicon-30, suggesting
that the stars that exploded to create the cloud were also rich in these
isotopes.
Donald Clayton of Clemson University in South Carolina said at a meeting in
Hawaii last week that this composition is more likely to match that of stars in
the centre of the Galaxy rather than those in the vicinity of the Sun, which is
roughly half way towards the edge.
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Clayton concludes that some of the Sun鈥檚 stellar ancestors began their lives
near the centre of the Galaxy and then moved outwards in their orbits.
This may have happened because the stars were constantly deflected by the
gravity of molecular clouds, he says: 鈥淢any would have ended their lives near
the cloud from which the Solar System formed and deposited their dust
迟丑别谤别.鈥�