Abstract
Ices of well-known composition are widely observed in molecular clouds out of which stars, planets and debris (asteroids, comets) will form. These ices are naturally subjected to energy input in the form of UV photons and charged cosmic particles which are able to start a very rich radical chemistry in the solid state. These phenomena are simulated in the MICMOC experiment which focuses on the possible prebiotic significance of the organic residues that are formed at room temperature. Further than MICMOC, we propose a general prospective of the evolution of this experiment toward the concept of non-directed experiments that may allow simulating the very first steps from the inanimate molecular world to selective pathways toward self-replicating autocatalytic and heterotrophic molecules that could be considered, for a physicist a template for “minimal” life.
Highlights
Ices of well-known composition are widely observed in molecular clouds out of which stars, planets and debris will form
The growth of infrared astronomy with IRAS, ISO and Spitzer satellites did allow the detection of many and abundant species in the solid phase, under the generic name “interstellar ices”, mostly in protostellar objects where ices are detected in the collapsing molecular cloud material that is located in front of the IR source formed by the interaction of the protostar with the infalling material
Other solid phase molecules can be attributed to energetic processing, where UV photons have usually been more employed than cosmic rays, it should be stressed that the effects of cosmic rays are remarkably similar, as far as the build-up of more complex molecules is considered
Summary
Interstellar ices are well known since a very long time, thanks to the advent of infrared spectroscopy in astronomy in the mid 70’s. It was not until 1979 that water ice was shown to explain the strong and very broad absorption band observed in the BN-KL object in Orion [1]. Because of grain accretion of the gas phase species, solid state molecules (H2O, CO, H2CO, CH3OH), in a given line of sight, always dominate in abundances their gas phase counterparts by one to three orders of magnitude. An excellent review on icy molecules can be found in [6] from which Figure 1 is extracted, and complementary information can be obtained in [7]
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