Silicon in carbonaceous chondrite metal: Relic of high-temperature condensation

Electron microprobe analyses of an extraordinarily large metal grain from the Murchison type 2 carbonaceous chondrite gave 0.24 mole percent silicon. Thermodynamic calculations show that this is a natural consequence of condensation of alloys from the solar nebular gas at a total pressure l0(-5) less, similar P(tot)l0(-3) atmosphere, provided they failed to equilibrate with it after cooling to1200 kelvins.