Detection of water ice on the Centaur 1997 CU26

We report the detection of the 1.5 and 2.0 mu m absorption bands due to water ice in the near-infrared reflection spectrum of the Centaur 1997 CU(26), which is currently located just outside the heliocentric distance of Saturn. The water ice hands are weaker than those detected on the surface of any other solar system body; the spectrum is well fit with a model surface consisting predominantly of a neutral dark absorbing substance with only similar to 3% areal coverage of water ice. The spectrum thus appears very different from that of the Centaur 5140 Pholus, although both objects are of similar brightness and are at similar heliocentric distances.