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.


something sounds fishy...

Co60 decays to Fe60 as demonstrated in the light curves of SN1987a
(the one in the Megallanic CLoud) as a supernova product.

from the physics i understand, xrays can't cause nuclear reactions, so
i'm hard pressed to understand how a youthful xray intense star can
produce Al26, unless its being produced in the star and blowing out of
it with the solar wind...