Science, Vol 256, Issue 5054, 204-206
Copyright © 1992 by American Association for the Advancement of Science
Solar control of the upper atmosphere of Triton
Lyons JR,
YL Yung,
and
M Allen
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena 91125, USA.
If the upper atmosphere and ionosphere of Triton are controlled by precipitation of electrons from Neptune's magnetosphere as previously proposed, Triton could have the only ionosphere in the solar system not controlled by solar radiation. However, a new model of Triton's atmosphere, in which only solar radiation is present, predicts a large column of carbon atoms. With an assumed, but reasonable, rate of charge transfer between N2(+) and C, a peak C+ abundance results that is close to the peak electron densities measured by Voyager in Triton's ionosphere. These results suggest that Triton's upper atmospheric chemistry may thus be solar-controlled. Measurement of key reaction rate constants, currently unknown or highly uncertain at Triton's low temperatures, would help to clarify the chemical and physical processes occurring in Triton's atmosphere.
