Reference heat capacity for Asteroid regolith from 10 to 1000K

Abstract

Introduction: Remote sensing in the mid-infrared allows the estimation of the thermal effusivity or ther- mal inertia Γ=(k(T)cp(T))1/2 of the surface material, with T absolute temperature, k thermal conductivity, ρ bulk density, and cp heat capacity at constant pressure in units of J/kgK. Knowledge or an estimate of cp(T) is required to extract, e.g., k(T), which in turn allows es- timation of grain sizes by applying models of heat transport in porous media [1-2]. While the temperature dependence of cp is a second-order effect at room temperature and does not strongly dependent on the chosen material (besides the mass fraction of metallic FeNi), cp shows very strong temperature and composition dependence at low tem- peratures. Heat capacity goes to zero as T approaches zero, and it is proportional to T³ at very low tempera- tures. It shows a slight linear increase as T approaches large values due to the difference cp – cv, as only cv obeys the 3R/atom Dulong-Petit limit.