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An Astronomical 2175 Å Feature in Interplanetary Dust Particles

2005; American Association for the Advancement of Science; Volume: 307; Issue: 5707 Linguagem: Inglês

10.1126/science.1106717

1095-9203

J. P. Bradley, Z. R. Dai, Rolf Erni, Nigel D. Browning, Gerard J. Graham, Peter Weber, Julie B. Smith, I. D. Hutcheon, H. A. Ishii, S. Bajt, C. Floss, F. J. Stadermann, Scott A. Sandford,

Astro and Planetary Science

The 2175 angstrom extinction feature is the strongest (visible-ultraviolet) spectral signature of dust in the interstellar medium. Forty years after its discovery, the origin of the feature and the nature of the carrier(s) remain controversial. Using a transmission electron microscope, we detected a 5.7-electron volt (2175 angstrom) feature in interstellar grains embedded within interplanetary dust particles (IDPs). The carriers are organic carbon and amorphous silicates that are abundant in IDPs and in the interstellar medium. These multiple carriers may explain the enigmatic invariant central wavelength and variable bandwidth of the astronomical 2175 angstrom feature.