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Insights from the Organic Inventory of Meteorites

スピーカー
Queenie Hoi Shan CHAN (KT NASA Johnson Space Center)
日付
February 5, 2016
時間
11:00
場所

ELSI-2 Building - 104 ELSI-Lounge

Abstract:
Carbonaceous chondrites represent a class of chondritic meteorites comprising primitive solar nebular aggregates that did not experience extensive planetary formation processes. They contain organic carbon materials that are soluble in common organic solvents. Carbonaceous chondrites may provide clues to the abiotic chemical evolution processes that predate and promote the onset of life and offer important insights into the target asteroids of the sample return missions Hayabusa-2 and OSIRIS-REx, which aim to collect and return to Earth samples from the surfaces of the C-type asteroids Ryugu and Bennu. Through detailing the organic molecule inventory in the early Solar System, and understanding the conditions and processes that occurred on the asteroid parent bodies, we may be able to develop testable hypotheses regarding pathways of abiotic developments of organic molecules. Life on Earth shows preference towards the set of organics with particular spatial configurations. While this 'selectivity' is a crucial criterion for life, enantiomeric excesses have also been observed for α-methyl amino acids in meteorites, which suggests that chiral asymmetry might have an abiotic origin. A possible abiotic mechanism that could produce chiral asymmetry in meteoritic amino acids is their formation under the influence of asymmetric catalysts, as mineral crystallization can produce spatially asymmetric structures. In this talk, I will discuss about the state-of-the-art laboratory techniques used to study the organic contents of meteorite samples, various symmetry-breaking mechanisms that can initiate a small enantiomeric excess, and how the study of organics in meteorites may provide important insights into life's origin.

* she will give us her talk via Skype*