The molecular chemistry of nanoscale organic matter in asteroid Ryugu

Abstract

The analysis of biorelevant molecules in returned mission samples such as from the carbonaceous asteroid (162173) Ryugu is key to unravelling the role of extraterrestrial organics in the evolution of life. Coordinated analyses using chemically non-destructive techniques at the finest length-scales on pristine samples are particularly important. Here, we identify the chemical signature of uncommon globular and nitrogen-containing diffuse composite organic matter in asteroid Ryugu and map the distribution of biorelevant molecules therein with unprecedented detail. Using a novel electron-microscopy-based combination of vibrational and core-level spectroscopy, we disentangle the chemistry and nanoscale petrography of these organics. We show that some of these organics contain soluble and highly aliphatic components as well as NHx functional groups, that have formed in outer solar nebula environments before parent body incorporation or were synthesized by subtle fluid reactions on the final Ryugu asteroid. These novel coordinated analyses will open up new avenues of research on these types of precious and rare asteroidal dust samples.