ICES ON THE SURFACE OF TRITON

The near-infrared spectrum of Triton reveals ices of nitrogen, methane , carbon monoxide, and carbon dioxide, of which nitrogen is the domina nt component. Carbon dioxide ice may be spatially segregated from the other more volatile ices, covering about 10 percent of Triton's surfac e. The absence of ices of other hydrocarbons and nitriles challenges e xisting models of methane and nitrogen photochemistry on Triton.