INTERSTELLAR DUST AS THE SOURCE OF ORGANIC MOLECULES IN COMET

Interstellar dust is described as consisting predominantly (by mass) of tenth micron (mean size) silicate core—organic refractory mantle particles which have evolved over galactic time scales of the order of 5 billion years. These particles were incorporated into comets and asteroids in the presolar nebula 14.5 billion years ago. The fragmentation of those primitive bodies gives rise to solar system debris which shows up as comet dust, zodiacal light, IDP’s and meteorites. The chemical and morphological structure of comet dust is derived here as fluffy aggregates of interstellar dust. The chemical and morphological structure of the chondritic porous IDP’s are then derived from comet dust which has evolved in the solar system. Zodiacal light particles are interpreted as various stages between comet dust and IDP’s. Meteorites appear to be a side branch in the evolution from interstellar to solar system particles