Production rate of H2O molecules as indicator of the surface temperature of cometary nucleus

Abstract

The technique outlined by Feynman (1963) to compute the number of molecules evaporating from a liquid surface has been extended to compute the sublimation rate of H2O molecules from the surface of a cometary nucleus and hence its surface temperature. The application of this technique to a cometary nucleus of typical radius 2.5 km and having a production rate of H2O molecules as 10 exp 29 per second yields 263 K as its surface temperature using iteration method. The error involved is estimated as +/- 5 K if the radius of the nucleus is changed by 0.5 km from the adopted value of 2.5 km