Water ice on Kuiper Belt object 1996 TO66

The 1.40-2.45 mu m spectrum of Kuiper Belt object 1996 TO66 was measured at the Keck Observatory in 1998 September. Its spectrum shows the strong abso rptions near 1.5 and 2.0 mu m that are characteristic of water ice-the firs t such detection on a Kuiper Belt object. The depth of the absorption bands and the continuum reflectance of 1996 TO66 suggest the presence of a black - to slightly blue-colored, spectrally featureless particulate material as a minority component mixed with the water ice. In addition, there is eviden ce that the intensity of the water bands in the spectrum of 1996 TO66 varie s with rotational phase, suggesting a "patchy" surface.