Evidence of aqueous alteration and ongoing molecular evolution in the asteroid Ryugu: abiotic precursor of amino acids and nucleobases

Key points of the results:

• We revealed that asteroid Ryugu contains diverse hydrophilic organic acids (including 65 newly identified species such as oxalic acid, malonic acid, citric acid, malic acid, pyruvic acid, lactic acid, and mevalonic acid) and nitrogenous compounds (including 19 newly identified species such as alkylurea, an organic-inorganic complex). The presence of abiotic precursor molecules such as amino acids and nucleobases, which are the sources of molecular evolution, has been identified for the first time.

• Based on the tautomerism of malonic acid (a dicarboxylic acid), we showed evidence that asteroid Ryugu has been a water-rich parent body in the history. A comprehensive observation of the light element abundances (carbon, nitrogen, hydrogen, oxygen, sulfur) and stable isotopic compositions at two sampling sites on asteroid Ryugu, has summarized on the record of chemical evolution through water, organic molecules and mineral interactions.

• The synergy of cutting-edge analytical techniques at the elemental and molecular levels are promising for further advanced sciences. We provide important evaluation for comparative studies between two asteroids of Ryugu and Bennu. The present findings offer insights into the nature and molecular diversity of primordial history in the Solar System and are significant for exploring the abiotic chemical evolution.

For more details, please see the Nature Communication link:

DOI: 10.1038/s41467-024-49237-6

Unraveling the historical records: primordial aqueous alteration in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu.