Meteoritics

CONDOR – Applications

As noted on the page above, the CONDOR code has been used for modeling chemistry in the solar nebula. An important aspect of this modeling is condensation temperature calculation for minerals in a solar composition gas or in a near-solar composition gas. Traditionally, cosmochemists have interpreted condensation temperatures as the temperatures where different minerals begin to condense from a cooling gas, but a condensation temperature can also be interpreted as the highest temperature at which a mineral is stable in a mixture of gas plus dust that is being heated up.

The two tables below are taken from the paper by Lodders and Fegley (1993) and give the condensation temperatures for important refractory minerals in a solar gas (with a carbon to oxygen atomic ratio of ~0.48) and in a reducing gas (with a higher C/O atomic ratio of 1.2). The results from the CONDOR code are compared to previously published calculations from the literature. The small differences are discussed by Lodders and Fegley (1993) and are due to the use of updated elemental abundances and thermodynamic data in their calculations.


Table 1.

Condensation temperatures of refractory minerals in a solar gas*
Condensation Temperature (K)
Mineral Ideal Formula CONDOR (LF93) KF84 and PF90 LG78 and G88
corundum Al2O3 1772 1741a 1749c
hibonite CaAl12O19 1748 1730a 1725c
perovskite CaTiO3 1687 1677a 1675c
gehlenite Ca2Al2SiO7 1624 1608a 1607c
spinel MgAl2O4 1505 1488a 1494c
iron metal Fe 1453 1458b 1458d
forsterite Mg2SiO4 1442 1429b 1433d

*At a pressure of 10-3 bar. aKornacki and Fegley 1984. bPalme and Fegley 1990. cGrossman et al. 1988. dLattimer and Grossman 1978. The literature work used elemental abundances from Cameron (1982).


Table 2.

Condensation of refractory minerals at C/O = 1.2 and 10-3 bar*
Condensation Temperature (K)
Mineral Ideal Formula CONDOR (LF93) F82 LG78
titanium carbide TiC 1893 1888 1893
graphite C 1766a 1735 1732
moissanite SiC 1736 1740 1742
cohenite Fe3C 1453 1454 1463
aluminum nitride AlN 1398 1389 1396
oldhamite CaSb 1379 1313 1385
forsterite Mg2SiO4 1152 1146 1154
osbornite TiN 1015 1021 1025

*The C/O ratio was increased by adding carbon. aGraphite condenses at 1734 K if the solar abundances of Cameron (1982) are used, as was done in Fegley (1982) and Lattimer and Grossman (1978). bSears et al. (1983) condense CaS at 1377 K at 10-3 bars.


References

  1. Cameron, A. G. W. 1982. Elementary and nuclidic abundances in the solar system. In Essays in Nuclear Astrophysics (C. A. Barnes, D. D. Clayton, and D. N. Schramm, Eds.) pp. 23-43. Cambridge University Press, New York.
  2. Fegley, B. Jr. 1982. Chemical fractionations in enstatite chondrites (abstract). Meteoritics 17, 210-212.
  3. Grossman, L., C. A. Geiger, O. J. Kleppa, B. O. Mysen and J. M. Lattimer 1988. Stability of hibonite and CaAl4O7 in the solar nebula. LPSC XIX, 437-438.
  4. Kornacki, A., and B. Fegley, Jr. 1984. Origin of spinel-rich chondrules and inclusions in carbonaceous and ordinary chondrites. J. Geophys. Res. 89, B588-B596.
  5. Lattimer, J. M., and L. Grossman 1978. Chemical condensation sequences in supernova ejecta. Moon Planets 19, 169-184.
  6. Lodders, K., and B. Fegley, Jr. 1993. Lanthanide and actinide chemistry at high C/O ratios in the solar nebula. EPSL 117, 125-145.
  7. Palme, H., and B. Fegley, Jr. 1990. High temperature condensation of iron-rich olivine in the solar nebula. EPSL 101, 180-195.
  8. Sears, D. W., G. W. Kallemeyn and J. T. Wasson 1983. Composition and origin of clasts and inclusions in the Abee enstatite chondrite breccia. EPSL 62, 180-192.