Exploring the organic chemistry of the early solar system using molecular isotopic structure

Organic chemistry is ubiquitous across extraterrestrial environments and dominates the processing and delivery of carbon and nitrogen to rocky planetary bodies. Extraterrestrial settings and materials also present the most clearly revealed and diverse collection of constraints on the ways in which ‘prebiotic’ chemistry takes its first steps towards life. Some of the most detailed and nuanced constraints on this subject come from the laboratory study of the thousands of organic compounds sampled by carbonaceous meteorites and returned samples of asteroids. However, detailed understanding of these materials has been challenging because they may be intimate mixtures of the products of chemistry operating across many settings and processes.

I will explore the origin and evolution of early solar system organic materials through application of molecular isotopic structure - the study of the distributions of naturally occurring rare isotopes (D, 13C, 15N, etc.) at scales of individual atomic positions and considering the very rare versions of molecules that contain two or more rare isotopes. These studies were enabled by more than two decades of inventions in mass spectrometry, studies of the chemical physics of previously unexamined isotopic forms of molecules, and applications to meteorites, returned samples, ancient earth materials and their laboratory analogues. The results reveal the long, complex journey of carbon and other volatile materials from synthesis in the interstellar medium, through the early history of the protoplanetary disk and into the ‘prebiotic cauldron’ of solar system bodies.

Speaker: John Eiler, California Institute of Technology