Spectral studies of extra-terrestrial materials

• Main Author: Fernandes, Catarina
• Published: Open University 2012
• Subjects: 523.51
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594252

Experiments were made using a state-of-the-art UV-Vis microspectrophotometer (MSP) in order to assess if the instrument is suitable for use on spectroscopy of terrestrial and extra-terrestrial materials. This new instrument brings advantages that cannot be found in instruments currently in use: it requires only extremely small samples (min of -2 um) and it is very quick to use (little sample preparation and spectra taken in less than 2 min). If suitable, the instrument could help to show the relationship between meteorites and their parent bodies and in the study ' of very small fragile samples, such as cometary samples and Interplanetary Dust Particles (IDPs). Using samples of minerals commonly found in meteorites, it was concluded that the instrument is suitable for the study of these materials, however it has some limitations and certain conditions need to be met. The method was then applied on two grains from comet 81P/Wild 2 returned by the space mission Stardust. Further limitations were found with these samples caused by the fact that they are covered in aerogel and embedded in gold foil. Results indicate however, that the samples seem to be composed of a mixture of different materials. Results from the study of HED (howardites, eucrites and diogenites) type meteorites proved that if the conditions are met, the technique is suitable and comparable to other instruments and can be used to match the spectra of meteorites to that of their possible asteroidal parent bodies. A complementary investigation studied the effects of impact by shock on the spectra of rocks using a Light Gas Gun and Near Infrared spectroscopy with the goal of investigating the effects of weathering on the spectra of asteroids. It was found that there is a change in the spectra of the samples and a relationship with a change in composition of the impacted area.