"BC" == Bob Carlson writes:

Critical to the team's argument is the recent discovery in
meteorites of patterns of isotopes that can only have been caused
by the radioactive decay of iron-60, an unstable isotope that has a
half life of only a million and a half years. Iron-60 can only be
formed in the heart of a massive star and thus the presence of live
iron-60 in the young Solar System provides strong evidence that
when the Sun formed (4.5 billion years ago) a massive star was
nearby.

BC Elsewhere I read it is nickel-60, decaying from iron-60, that is
BC found in meteorites on earth. Is this true? Are there any other
BC elements that would provide the telltale signs of having been
BC formed in massive stars?

There's been a long standing puzzle that aluminum-26 decay products
also are found in some meteorites. Aluminum-26 has a very short
half-life (9 million years?) which has been interpreted as implying
that a massive star must have gone supernova within a few million
years of the formation of the solar system. More recently, however,
Frank Shu and others have proposed that the X-ray activity of the
young Sun may have been enough to produce the Al-26. It would be
interesting to hear that team's thoughts on this new proposal.

--
Lt. Lazio, HTML police | e-mail:
No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html