Seminar: New route to diamond in meteorites: resolving the puzzle of pre-solar origin

A/Prof Nigel Marks 

Curtin Nanochemistry Research Institute

Primitive chrondritic meteorites provide a fascinating window into the history of the galaxy and solar system by directly preserving chemical and isotopic information inside tiny diamond grains. The formation process of these nanodiamonds has long been controversial. By combining observational information with atomistic simulation we discover a new way of forming nanodiamond. In this process carbon onions condense from vapour and subsequently collide to form nanodiamond. Our process complies with astrophysical constraints and is the first model consistent will all key features of meteoritic nanodiamond, that is, size, shape, polytype and isotopic composition. While some nanodiamonds are undoubtedly pre-solar in origin, we conclude that nanodiamonds in meteorites do not necessarily pre-date the formation of the solar system as previously thought.