Compositional trends in rock-forming elements of comet Halley dust
M N Fomenkova1, J F Kerridge, K Marti
1Space Research Institute, Academy of Sciences, Moscow, Russia.
Abstract:
The VEGA 1 and 2 spacecraft flew by comet P/Halley in 1986 carrying, among other instruments, two mass spectrometers to measure the elemental composition of dust particles emitted from the comet. Most particles seem to be a mixture of silicates of variable magnesium-iron composition and organic matter. Comprehensive study of data and consideration of the mass of dust particles reveal cometary grains of "unusual" composition: magnesium-rich and iron-rich particles. Magnesium-rich particles are most likely magnesium carbonates, which could not have formed under conditions of equilibrium condensation but rather require formation by aqueous alteration. The composition of the iron-rich particles can also be related to secondary processes in the comet.
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