Thermophysical modelling of Comet P/Borrelly : Effects of volume energy absorption and volume sublimation

• In this work, 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 are significantly smaller than the ones in the surface-absorbing model. An active fraction of 40-50% 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.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

Cometary nuclei

P/Borrelly

surfaces

thermal models

Planetary system

Planetsystemet

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