The highly anticipated samples from asteroid (101955) Bennu have been released, providing a wealth of information about the composition and origins of this carbonaceous chondrite. As part of the OSIRIS-REx mission, scientists collected and returned samples to Earth in 2023, offering a rare opportunity for scientists to study an extraterrestrial sample up close.
The Bennu samples are rich in organic molecules, including amino acids, heterocycles, polycyclic aromatics, and DNA/RNA nucleobases. These findings suggest that the asteroid’s parent body underwent low-temperature aqueous chemistry in an environment where ammonia ice was stable. This hypothesis is supported by the diversity of evaporate minerals found in the Bennu material.
The samples also reveal a high concentration of volatiles, including ammonia and formaldehyde, which are difficult to assay accurately. The composition of these molecules provides valuable insights into the formation and evolution of organic compounds in our solar system.
Notably, 14 out of 20 naturally occurring amino acids were detected, with glycine being the most abundant. However, non-canonical amino acids were also present, suggesting a diverse range of chemical processes that occurred on Bennu.
The similarity between the Bennu samples and those from the Ryugu asteroid highlights the universality of organic chemistry in our solar system. In contrast, the Murchison meteorite is richer in extraterrestrial material, suggesting that life may have seeded our planet with enantiomerically enriched amino acids.
These findings provide strong evidence for the presence of simple organic molecules throughout our solar system and beyond. The discovery of these compounds on asteroids like Bennu underscores the idea that starting materials are abundant, but the emergence of life is still a complex and uncertain process.
Source: https://www.science.org/content/blog-post/fresh-asteroid-getcher-fresh-asteroid-here