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An astronomical 2175 angstrom feature in interplanetary dust particles.
John Bradley1, Zu Rong Dai, Rolf Erni
1Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. jbradley@igpp.ucllnl.org
Science (New York, N.Y.)
|January 18, 2005
Summary
The interstellar medium's 2175 angstrom extinction feature is identified in interplanetary dust particles. Organic carbon and amorphous silicates are the likely carriers, explaining its consistent wavelength.
Area of Science:
- Astronomy and Astrophysics
- Cosmic Dust Studies
- Spectroscopy
Background:
- The 2175 angstrom extinction feature is a prominent spectral signature of interstellar dust.
- Its origin and the identity of the responsible dust components remain debated after decades of research.
Purpose of the Study:
- To investigate the carriers responsible for the 2175 angstrom interstellar extinction feature.
- To analyze the composition of interstellar grains within interplanetary dust particles (IDPs).
Main Methods:
- Utilized transmission electron microscopy (TEM) to examine interstellar grains.
- Analyzed the spectral properties of dust components within IDPs.
Main Results:
- Detected the 5.7-electron volt (2175 angstrom) feature in interstellar grains within IDPs.
- Identified organic carbon and amorphous silicates as the primary carriers of this feature.
- Observed that these carriers are common in both IDPs and the interstellar medium.
Conclusions:
- Organic carbon and amorphous silicates are identified as key carriers of the 2175 angstrom interstellar extinction feature.
- The presence of multiple carriers provides a plausible explanation for the feature's invariant central wavelength and variable bandwidth.
- This finding advances our understanding of interstellar dust composition and its spectral properties.
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