The measurement of meteorite heat capacity at low temperatures using liquid nitrogen vaporization

• A novel system to measure whole-meteorite heat capacity at low temperature.
• Accurate, rapid, non-destructive, inexpensive.
• Can be used to model planetary processes, characterize whole meteorite samples.
• First results show trends with metal, nickel, and OH content and with weathering.
• Results consistent with previous (sparse) literature data.

Meteorite heat capacity (specific heat) is an essential parameter in modeling many aspects of the orbital and internal evolution of small solar system bodies, and can be a tool for characterization of the material in a meteorite itself. We have devised a novel method for the measurement of this quantity in whole-rock samples of meteorites, at low temperatures typical of asteroids. We insert the sample in liquid nitrogen, measure the mass of nitrogen boiled off due to the heat within the sample, and calibrating against measurements of pure quartz with a temperature-averaged heat capacity of 494 J/kg K we calculate the temperature-average heat capacity of the sample. We show that this method is accurate, rapid, inexpensive, and non-destructive. Preliminary results for chondrites and metal rich meteorites are in excellent agreement with the literature data for meteorites, and hold the promise that such measurements may not only produce values useful to modelers but they also may provide an efficient way to classify whole meteorite samples and characterize subtle differences between meteorites of different compositional classes.