Stony meteorite thermal properties and their relationship with meteorite chemical and physical states |
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| Authors: | C P OPEIL SJ G J CONSOLMAGNO SJ D J SAFARIK D T BRITT |
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| Institution: | 1. Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467–3804, USA;2. Specola Vaticana, V‐00120, Vatican City, Vatican City State;3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA;4. Department of Physics, University of Central Florida, Orlando, Florida 32816–2385, USA |
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| Abstract: | Abstract– In our ongoing survey of meteorite physical properties, we have to date measured the thermal conductivity for seventeen stony meteorites at temperatures ranging from 5 K to 300 K. Here, we report new results for nine ordinary chondrites, one enstatite chondrite, and the basaltic achondrites Frankfort (howardite) and Los Angeles (shergottite). We find that thermal conductivity is significantly lower than would be expected from averaging the laboratory conductivities of their constituent minerals, with a dependence on temperature different from the expected conductivity of pure minerals. In addition, we find a linear relationship between the inverse of the porosity of the samples measured and their thermal conductivity, regardless of meteorite composition or type. We conclude that thermal conductivity is controlled by the presence of shock‐induced microcracks within the meteorites, which provide a barrier to the transmission of thermal energy via phonons. In contrast to conductivity, our first measurement of heat capacity as a function of temperature (on Los Angeles) suggests that heat capacity is primarily a function of oxide composition and is not strongly affected by the physical state of the sample. |
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