Thermophysical modelling of comet P/Borrelly effects of volume energy absorption and volume sublimation

• Published in: Earth, moon, and planets Vol. 2; no. 1-4; pp. 293 - 303
• Main Authors: Skorov, Y V, Keller, H U, Jorda, L, Davidsson, B J R
• Format: Journal Article
• Language: English
• Published: 01-03-2002
• ISSN: 0167-9295

We continue revising the theoretical basis of numerical models describing the transport of matter and energy inside a porous dust-ice mixture at low temperature. A model of a light-absorbing near-surface layer of a comet nucleus is investigated. Gas transport is considered simultaneously with the solution of the general heat transfer equation. The quasi-stationary temperature distribution and the H2O mass flux and sublimation rate are computed for a nucleus model of Comet 19P/Borrelly at the Deep Space 1 (DS1) encounter. The energy is deposited in a layer of about 20 particle radii. This corresponds to a solid-state greenhouse effect. The surface temperature of the layer-absorbing model, as well as the gas production rate, is significantly smaller than that in the surface-absorbing model. An active fraction of 40-50 percent would be required to explain the observed water production rate of P/Borrelly with our layer-absorption model at the time of the DS1 encounter. (Author)