Extraterrestrial Particles Examined by Shifted Excitation Raman Difference Spectroscopy

Abstract

Shifted Excitation Raman Difference Spectroscopy (SERDS) was applied to extraterrestrial particles. These particles were returned from an S-type near-Earth asteroid 25143 (“Itokawa”) by the JAXA space probe mission “Hayabusa” in 2010. Sample return missions are of particular interest for space research, because of the available state-of-the-art ground-based techniques and instrumentation. After complex treatments for first investigations such as in, the particles were examined with Raman spectroscopy. These Raman spectra are as a rule masked by a broad intense background, dominantly due to enhanced fluorescence, and do not allow clear interpretation. SERDS was applied using 488 nm laser excitation wavelength in order to separate the Raman signal from the background and therefore, to enable clear identification of mineralogical composition of the particles. Knowledge of the mineralogical composition is, among others, a necessary condition for the derivation of the particles’ exposure ages that are important for understanding the evolutionary history of the asteroid’s regolith.