Chemical Links between IRAS16293-2422B and 67P/C-G
Séminaire IPAG de Maria Drozdovskaya (CSH Bern), jeudi 11 octobre 2018 à 11h00, salle Manuel Forestini
Comet 67P/Churyumov-Gerasimenko has been studied with in situ measurements by various instruments (ROSINA, COSAC, VIRTIS, MIRO, ALICE, etc.) aboard the Rosetta spacecraft, which show that the comet has a rich molecular inventory and that there are complex relationships between various species. These data are one of the best probes of the innate protosolar disk that evolved into our modern day Solar System. Similar chemical richness, including large complex organic species, extends beyond the Earth and our Solar System as attested by countless observations towards high- and some low-mass protostars. One of the best-studied low-mass systems is IRAS16293-2422, which is thought to be analogous to the earlier phases of our Solar System. The region has been surveyed with the large unbiased ALMA Protostellar Interferometric Line Survey (PILS), which allowed its study with an unprecedentedly wide spectral range at high spectral and spatial resolutions. Thereby, its full chemical inventory and the spatial distribution of the detected species could be uncovered. This ALMA data on IRAS16293-2422 can be used to probe the extrasolar chemical content and the Rosetta measurements of 67P/C-G as a Solar System diagnostic. By deriving relative ratios for simple and complex organic molecules, direct comparisons can be drawn between the two to go after the origins of the chemical content of our Solar System. In this talk, results of such a comparative study will be presented, based on relative ratios of major and minor volatile species to access the degree of relative complexity stemming from common parent species. These results give clues to the different radicals available in the ices for subsequent synthesis of larger molecules, shedding light on the dominant pathways to chemical complexity and the physical conditions that optimize such enrichment. The carried out comparative work between protostars and 67P/C-G gives hints on the uniqueness of the ingredients to life.