Silicon in Carbonaceous Chondrite Metal: Relic of High-Temperature Condensation

Abstract
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 ≲ Ptot < l0–3 atmosphere, provided they failed to equilibrate with it after cooling to < 1200 kelvins.