Fig. 3. Representative IRIS Spectra of the Four Galilean Satellites.

Each is among the warmest available for that body (except that the Io spectrum does not include any hot-spots). All are from Voyager1 except the Europa spectrum, which is Voyager 2. The spectra have been smoothed, before conversion to T_B, by a boxcar filter of width 28 cm^-1. However, except in the Io spectrum all visible structure is probably noise. The spectra are: Io, 16389.29; Europa, 20650.47; Ganymede, 16402.23; and Callisto, 16421.59 (also shown unsmoothed in Fig. 1).
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