The effect of C / O ratio on the condensation of planetary material
Abstract
The condensation temperatures of refractory silicates and oxides in a gas of cosmic composition are strongly dependent on the C/O ratio. As the ratio increases from 0.4 to 0.9 (solar cosmic 0.6), condensation temperatures of compounds such as A1 2O 3, Ca 2Al 2SiO 7, MgAl 2O 4, Mg 2SiO 4 and MgSiO 3 decrease by 50-100°. As C/O increases from 0.9 to 1.0, these temperatures drop an additional 300-400°. Other chemical differences result when C/O$̆0.9 include: a new suite of high temperature minerals appears (graphite, CaS, Fe 3C, SiC and TiN); the reaction CO + 3H 2 → CH 4 + H 2O proceeds to the right at higher temperatures; and iron, whose condensation temperature is unaffected, condenses at higher temperatures than any silicate or oxide.
- Publication:
-
Geochimica et Cosmochimica Acta
- Pub Date:
- March 1975
- DOI:
- 10.1016/0016-7037(75)90204-5
- Bibcode:
- 1975GeCoA..39..389L
- Keywords:
-
- Abundance;
- Carbon;
- Condensation;
- Cosmic Gases;
- Oxygen;
- Planetary Evolution;
- Chemical Reactions;
- Nebulae;
- Refractory Materials;
- Silicates;
- Temperature Effects