Astrochemistry and Origins
An international scientific team including two co-Investigators from the IAS has determined the elemental composition of the dust of 67P/Churyumov-Gerasimenko, the comet explored by the European space probe Rosetta. Their results reveal some of the most carbon-rich materials and the least altered ever explored. This cometary carbon is essentially in a macromolecular organic structure, meaning that it is mainly in that form that it was delivered by comets to the primitive Earth.
The MICMOC experiment that started in 2003 at IAS and whose goal is to understand the link between astrochemistry and astrobiology, just came across through a major and surprising result: the prebiotic formation of the sugar molecule ribose, a key molecule toward the formation of RNA, the nucleic acid containing the first genetic material of living beings.
The interplanetary dust particles commonly called IDPs are micrometric extraterrestrial grains (typical size of ten microns). They are collected by NASA’s stratospheric aircrafts (at an altitude of ~ 25 km). Their origin asteroidal and/or cometary has always been a subject of investigation. In recent years we have conducted a systematic analysis of IDPs using infrared micro-spectroscopy through a collaboration with the SMIS beamline at the SOLEIL synchrotron. This work reveals, in one hand, the connection between asteroids/comets and extraterrestrial material collected for laboratory studies, and gives in another hand, valuable information on the relationship between organic matter and mineral phases probably due to physical and chemical processes in the primitive nebula.
A multidisciplinary team involving researchers from the IAS, the CIMAP, the IPNO, the GANIL, and Rio de Janeiro's PUC Catholic University has characterized in the laboratory the effects of heavy cosmic rays on the structure and sputtering of water ice in interstellar and planetary environments. These experiments are used to study phase changes induced by swift heavy ions, similar to the Galactic cosmic rays. They complement and extend the knowledge already obtained at lower energies. In addition to the ice phase change, these studies reveal the importance of water ice molecules released in the gas phase by swift heavy Galactic ions, or sputtering of interstellar ices present in dense and cold interstellar clouds.
Ten aldehydes, including two sugars potentially important for prebiotic chemistry, have for the first time been identified in organic residues issued from photochemistry of interstellar ice analogues, produced in the laboratory by the IAS MICMOC/SUGARS experiment.