Recent nanoscale analysis of Bennu sample OREX-800066-3, obtained from NASA’s groundbreaking OSIRIS-REx mission, reveals organic compounds and minerals are strategically clustered in distinct regions. This indicates that water once altered the asteroid in a heterogeneous and localized manner.
Mosaic image of asteroid Bennu captured by OSIRIS-REx’s PolyCam instrument on December 2, 2018, from a distance of 15 miles (24 km). Image credit: NASA / NASA Goddard Space Flight Center / University of Arizona.
Classification of Bennu as a primitive carbonaceous asteroid marks it as one of the best-preserved remnants from the early Solar System.
While meteorites are typically viewed as a source of primitive asteroid material, they face risks of alteration during atmospheric entry and potential contamination on Earth.
In contrast, the samples returned by Bennu are regarded as truly pristine, significantly enhancing the reliability of the findings derived from them.
In a recent study, scientists at Stony Brook University employed nanoscale infrared and Raman spectroscopy to analyze the chemical composition of OREX-800066-3 samples, achieving a spatial resolution ranging from 20 to 500 nanometers per pixel.
All analyses were conducted without exposing the samples to air, preserving sensitive chemical bonds and organic functional groups crucial for accurate detection.
Furthermore, both techniques utilized are non-destructive, which is vital considering the irreplaceable nature of these samples.
At the nanoscale, the fundamental building blocks of asteroid mineralogy and organic chemistry can be investigated within these precious specimens.
The new analysis pinpointed distinct chemical domains, including regions rich in aliphatic compounds, carbonate materials, and nitrogen-containing organic substances.
This finding indicates that water-induced alterations on Bennu are chemically heterogeneous.
Interestingly, nitrogen-rich organic functional groups are preserved despite extensive water-mediated changes.
“These findings have extensive implications for planetary science and astrobiology,” stated Mehmet Yeşiltas, a professor at Stony Brook University.
“They illustrate the survival of chemically sensitive nitrogen-containing organic matter through water alterations in small solar system bodies, impacting fundamental questions about the formation and preservation of organic complexity within primitive planetary material.”
“This may shed light on how organic compounds linked to prebiotic chemistry were delivered to early Earth via carbonaceous asteroids, potentially influencing the chemical processes that led to the origin of life.”
The full study result will be published in Proceedings of the National Academy of Sciences.
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Mehmet Yesiltas et al. 2026. Nanoscale infrared spectroscopy reveals the complex organo-mineral assemblage of asteroid Bennu. PNAS 123 (14): e2601891123; doi: 10.1073/pnas.2601891123
Source: www.sci.news
