Macromolecules: From Star-Forming Regions to Comets to the Origins of Life

Molecules of increasing complexity are being found in comets. Comets played an important role in delivering water and other volatiles to the terrestrial planets in the early history after their formation. They also may have supplied essential prebiotic organics to the early Earth. Macromolecules with potential links to biological molecules have been identi.ed in the gas phase in hot cores of massive star-forming regions. They are now also found in hot cores of star-forming clouds of low mass stars similar in size to the Sun. A close relationship between the list of cometary molecules and interstellar molecules suggests that macromolecules existed also in the solar nebula. These results strengthen the perception that molecules of biological interest may be found in comets. To pursue this argument successfully, we must link the relationship of ices in the interstellar medium with ices in comets and establish more .rmly the production of complex molecules by laboratory simulations of interstellar conditions involving these ices. We discuss observational links between the interstellar sources of macromolecules and their reservoirs in comets via the solar nebula.