Previously published observations of the lunar sodium exosphere during a passage through the Earth's magnetosphere (June 7-16, 1998) showed a drop in column abundance of equatorial sodium as the Moon entered into the magnetosphere, with a recovery after the lunar phase reached 30 degrees. At the same time, the temperature of the exosphere increased from a minimum of 1200 K to a maximum of 3000 K at minimum phase angle. Simultaneous data from the Lunar Prospector Electron Reflectometer reveal that the measured sodium column abundance is correlated with the total electron flux, which is used as a proxy for the ion flux. We present strong evidence that ion impact enhances the photon-stimulated desorption (PSD) yield. Inside the magnetosphere, where the ion flux and the associated PSD yield decrease, we find that the observed column abundance and temperature have substantial contributions from impact vaporization.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007