CONDOR – Applications

Introduction

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)
MineralIdeal FormulaCONDOR (LF93)KF84 and PF90LG78 and G88
corundumAl2O317721741a1749c
hiboniteCaAl12O1917481730a1725c
perovskiteCaTiO316871677a1675c
gehleniteCa2Al2SiO716241608a1607c
spinelMgAl2O415051488a1494c
iron metalFe14531458b1458d
forsteriteMg2SiO414421429b1433d

*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)
MineralIdeal FormulaCONDOR (LF93)F82LG78
titanium carbideTiC189318881893
graphiteC1766a17351732
moissaniteSiC173617401742
coheniteFe3C145314541463
aluminum nitrideAlN139813891396
oldhamiteCaSb137913131385
forsteriteMg2SiO4115211461154
osborniteTiN101510211025

*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.