The near infrared spectrum of Miranda - Evidence of crystalline water ice

A spectrum from 1.2 to 2.5 mum of Uranus' small satellite Miranda obtained in June 1999 reveals strong water-ice signatures. It confirms the existence of a 2.0-mum water feature previously detected on Miranda and shows a strong second broad 1.5-mum water-ice absorption feature. The spectra also reveal a weak absorption band at 1.65 mum that is indicative of crystalline water ice. Reflectance models which combine the new spectra with new photometry indicate that the spectra are characteristic of a mostly water-ice surface, with a large fraction of carbonaceous or silicate contaminates, and the possible presence of ammonia hydrate, as implied by an apparent weak feature near 2.2 mum. The possible presence of other volatiles is also investigated. (C) 2002 Elsevier Science (USA).