[meteorite-list] Cometary Meteorites

[bernd.pauli at paulinet.de]

Michael wrote:

> I had always heard Murchison was thought to be cometary
> material. Does this ... indicate it has been ruled out?

Hi Michael and List,

Murchison is one of those carbonaceous meteorites that contain
interstellar, presolar grains (diamonds, graphite, silicon carbide).
These grains were incorporated into Murchison after formation in
the atmosphere of a low-mass star (like our Sun) that had reached
the red giant stage of its stellar life, and, on its way toward becoming
a white dwarf, started throwing off its outer shells (in other words, it
became a planetary nebula lke M27, the Dumbbell Nebula or M57,
the famous planetary in Lyra).

Best wishes,

Bernd