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Updated: Jul 10, 2026
09:13
Characterization of Ultra-fine Grained and Nanocrystalline Materials Using Transmission Kikuchi Diffraction
Published on: April 1, 2017
Diamonds in dense molecular clouds: a challenge to the standard interstellar medium paradigm
L J Allamandola1, S A Sandford, A G Tielens
1National Aeronautics and Space Administration, Ames Research Center, Mountain View, CA 94035.
Science (New York, N.Y.)
|April 2, 1993
Summary
Interstellar dust in dense clouds shows a unique diamond-like signature, unlike the CH2 and CH3 groups found in diffuse clouds. This discovery challenges existing models of interstellar material formation and evolution.
Area of Science:
- Astrochemistry
- Interstellar Medium Physics
- Materials Science
Background:
- The composition of interstellar dust varies between dense and diffuse regions.
- Organic molecules in dust play a crucial role in chemical evolution.
- Previous studies have not fully characterized the organic component in dense interstellar clouds.
Purpose of the Study:
- To investigate the organic composition of interstellar dust in dense clouds.
- To compare the organic signatures in dense and diffuse interstellar media.
- To understand the formation pathways of interstellar organic materials.
Main Methods:
- Infrared spectroscopy to detect C-H stretching bands.
- Analysis of spectral signatures of interstellar dust.
- Comparison of data from dense and diffuse interstellar environments.
Main Results:
- A novel infrared C-H stretching band was discovered, indicative of diamond-like material in dense clouds.
- Dust in diffuse interstellar medium is characterized by -CH2- and -CH3 groups.
- A significant dichotomy exists in the aliphatic organic component between dense and diffuse media.
Conclusions:
- The presence of interstellar diamond-like material in dense clouds challenges standard models of interstellar processes.
- This finding rules out certain models for meteoritic diamond formation.
- The formation of this diamond-like material is likely linked to common interstellar processes or stellar types.
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