Evidence for Crystalline Water and Ammonia Ices on Pluto's Satellite Charon
Michael E. Brown,
1
and Wendy M. Calvin
2
Observations have resolved the satellite Charon from its parent
planet Pluto, giving separate spectra of the two objects from 1.0 to
2.5 micrometers. The spectrum of Charon is found to be different from
that of Pluto, with water ice in crystalline form covering most of the
surface of the satellite. In addition, an absorption feature in
Charon's spectrum suggests the presence of ammonia ices. Ammonia
ice-water ice mixtures have been proposed as the cause of flowlike
features observed on the surfaces of many icy satellites. The existence
of such ices on Charon may indicate geological activity in the
satellite's past.
1 Division of Geological and Planetary
Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
2 Department of Geological Sciences, University of
Nevada-Reno, Reno, NV 89557, USA.
