Heat capacities of ordinary chondrite falls below 300 K

Abstract

Low-temperature specific heat capacities of meteorites provide valuable data for understanding the composition and evolution of meteorites and modeling the thermal behavior of their source asteroids. By liquid nitrogen immersion, we measured average low-temperature heat capacities for 60 ordinary chondrite falls from the Vatican collection. We further characterized the temperature dependence of ordinary chondrite by direct measurement of Cp(T) over the range 5–320 K for five OC falls, coupled by composition-based models for 94 ordinary chondrites. We find that the heat capacity as a function of temperature for typical ordinary chondrites can be closely approximated by a third-order polynomial in temperature. Furthermore, those polynomial coefficients can be estimated from the single-value average heat capacity measurement. These measurements have important implications for the orbital and spin evolution of S- and Q-type asteroids via the various Yarkovsky effects and the thermal evolution of meteorite parent bodies.