- Names
-
- L.G. Vacher
- V.T.H. Phan
- L. Bonal
- M. Iskakova
- O. Poch
- P. Beck
- E. Quirico
- R.C. Ogliore
- Title
- NH-rich organic compounds from the carbonaceous asteroids (162173) Ryugu: Nanoscale spectral and isotopic characterizations
- Abstract
- C-type asteroids may have played a key role in delivering volatile elements and prebiotic organic materials to early Earth. The MicrOmega reflectance spectra of Ryugu particles reveal spectral bands at 3.06 μm and 3.24 μm, indicating potential N−H chemical bonds. However, the exact nature of these bonds—whether related to N-rich organics, ammonium salts, or phyllosilicates—remains uncertain. In this study, we report the characterization of two Ryugu particles (C0050 and C0052) using multi-scale infrared (SHADOWS, μ-FTIR, and AFM-IR) and NanoSIMS techniques to constrain the nature and origin of NH bearing components in the Ryugu asteroid. Our findings show that Ryugu’s C0052 particle contain rare, micrometer-sized NH-rich organic compounds with C=O and N-H vibration modes, indicative of amide related compounds. Notably, N isotopic analysis reveals that these amides are depleted in 15N (d15N = −215 ± 92 ‰) and are therefore indigenous to the Ryugu samples. The amides can form abiotically under low temperature alteration conditions. However, given their depletion in 15N, we suggest they did not arise from hydrothermal alteration on Ryugu’s parent asteroid. Instead, we propose that these amides could have originated from the irradiation of 15N-depleted N-bearing ice (N₂ or NH₃) either from the outer Solar System or the interstellar medium. This implies that Ryugu's parent body may have inherited primordial organic material from regions beyond the H₂O−CO₂ snow lines, contributing possibly to the delivery of volatiles and organics to early Earth, where amides could have played a crucial role in prebiotic chemistry.
- Keywords
- asteroid, keyword, normalized reflectance spectra, transmission spectra
- Content
- spectral data, planetary sciences
- Year
- 2025
- Journal
- Meteoritics and Planetary Science
- Document type
- article
- Publication state
- unpublished