title: An astronomical 2175 angstrom feature in interplanetary dust particles.
abstract: 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.
authors.affiliation: Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. jbradley@igpp.ucllnl.org
authors.forename: John
authors.initials: J
authors.lastname: Bradley
authors.forename: Zu Rong
authors.initials: ZR
authors.lastname: Dai
authors.forename: Rolf
authors.initials: R
authors.lastname: Erni
authors.forename: Nigel
authors.initials: N
authors.lastname: Browning
authors.forename: Giles
authors.initials: G
authors.lastname: Graham
authors.forename: Peter
authors.initials: P
authors.lastname: Weber
authors.forename: Julie
authors.initials: J
authors.lastname: Smith
authors.forename: Ian
authors.initials: I
authors.lastname: Hutcheon
authors.forename: Hope
authors.initials: H
authors.lastname: Ishii
authors.forename: Sasa
authors.initials: S
authors.lastname: Bajt
authors.forename: Christine
authors.initials: C
authors.lastname: Floss
authors.forename: Frank
authors.initials: F
authors.lastname: Stadermann
authors.forename: Scott
authors.initials: S
authors.lastname: Sandford
mesh_terms: D002244:Carbon; D019443:Cosmic Dust; D006838:Hydrocarbons; D008670:Metals; D046529:Microscopy, Electron, Transmission; D009930:Organic Chemicals; D010100:Oxygen; D017640:Silicates; D013056:Spectrophotometry, Ultraviolet; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D019443:Cosmic Dust; D006838:Hydrocarbons; D008670:Metals; D009930:Organic Chemicals; D017640:Silicates; D002244:Carbon; D010100:Oxygen