CHAMPAIGN, Ill. -- The death of a massive nearby star billions
of years ago offers evidence the sun was born in a star cluster,
say astronomers at the University of Illinois at Urbana-
Champaign. Rather than being an only child, the sun could have
hundreds or thousands of celestial siblings, now dispersed
across the heavens. In a paper accepted for publication in the
Astrophysical Journal, astronomy professors Leslie W. Looney and
Brian D. Fields, and undergraduate student John J. Tobin take a
close look at short-lived radioactive isotopes once present in
primitive meteorites. The researchers' conclusions could reshape
current theories on how, when and where planets form around
stars. Short-lived radioactive isotopes are created when massive
stars end their lives in spectacular explosions called
supernovas. Blown outward, bits of this radioactive material mix
with nebular gas and dust in the process of condensing into
stars and planets. When the solar system was forming, some of
this material hardened into roc