Overview
- The finding makes Ryugu the second carbonaceous asteroid after Bennu with all five canonical nucleobases detected in returned samples.
- Comparisons with Bennu and the Murchison and Orgueil meteorites show distinct purine–pyrimidine patterns, with Ryugu roughly balanced, Bennu and Orgueil richer in pyrimidines, and Murchison richer in purines.
- The study reports a correlation between lower purine-to-pyrimidine ratios and higher ammonia levels, suggesting a chemical control that current formation models do not yet explain.
- Researchers used tightly controlled curation and cleanroom analyses with verification tests to indicate the molecules are indigenous rather than terrestrial contamination.
- Authors stress the detections do not indicate past life on Ryugu, instead supporting scenarios in which carbonaceous asteroids supplied prebiotic ingredients to early Earth and motivating further lab and sample analyses.