Near-Infrared Spectroscopy of Centaurs and Irregular Satellites
We have obtained near-infrared spectra of the four brightest known Centaurs and of five irregular satellites of giant planets. Many of these objects show 1.5 and 2.0 μm absorption bands indicative of water ice, including 1997 CU_(26), Pholus, Phoebe (S9), and Nereid (N2). The satellites of Jupiter—Elara, Himalia, and Pasaphae (J6, J7, J8)—appear spectrally featureless, consistent with asteroidal origins for these bodies. Phoebe's surface water ice indicates that it formed as an icy planetesimal rather than as an asteroid.
Additional Information© 2000 American Astronomical Society. Received 1999 July 13; accepted 1999 November 5. We would like to thank Chris Koresko and Geoff Blake for their generous help in obtaining these observations and an anonymous referee for useful suggestions. This research is supported entirely through private funding. These data were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The observatory was made possible by the financial support of the W. M. Keck Foundation.
Published - 1538-3881_119_2_977.pdf