Laboratory study of silicates and application to cometary dust

Summary The mass absorption coefficients of some glassy and crystalline silicates of astrophysical relevance have been measured. We produced and characterized also synthetic silicates of olivine type since this material is considered one of the most likely components of cometary dust grains. The experimental data are used to fit the emission feature observed in the Comet Halley spectrum between 8 and 13 μm. Satisfactory results are obtained by using synthetic olivine mixed with a small amount (5%) of crystalline grains. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.