The sublimation rate of ice is commonly calculated using the simple Hertz–Knudsen formula. This formula is derived from the kinetic theory of gases and ignores microphysical processes determining the actual sublimation rate. The microphysical processes can be accounted for by including the temperature dependent sublimation coefficient (Kossacki, K.J., et al. [1999]. Planet. Space Sci. 47, 1521–1530; Gundlach, B., Skorov, Y.V., Blum, J. [2011]. Icarus 213, 710–719). Kossacki and Markiewicz (Kossacki, K.J., Markiewicz, W.J. [2013]. Icarus 224, 172–177) discussed to what extent inaccuracy of the simple Hertz–Knudsen equation affects the calculated temperature of Comet 67P/Churyumov-Gerasimenko. Numerical simulations presented in Kossacki and Markiewicz (Kossacki, K.J., Markiewicz, W.J. [2013]. Icarus 224, 172–177) indicate, that derivation of the temperature below the dust mantle from the measured water production rate ignoring temperature dependence of the sublimation coefficient can lead to an underestimate of the temperature by more than 10 K. Thus, it is important to know the dependence on the sublimation coefficient of the composition of the real cometary ice, which can be far from purity.

We intended to check whether a small amount of dissolved minerals can affect the temperature dependence of the sublimation coefficient of ice. According to our experiments the answer is positive.