P21F-05:
The Teardrop Shaped Lunar Dust Exosphere
Tuesday, 16 December 2014: 9:00 AM
Jamey Szalay1,2, Mihaly Horanyi1,2, Sascha Kempf1,2, Eberhard Gruen2, Ralf Srama3 and Zoltan Sternovsky2,4, (1)University of Colorado at Boulder, Physics, Boulder, CO, United States, (2)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (3)University of Stuttgart, Stuttgart, Germany, (4)University of Colorado at Boulder, Aerospace Eng. Sciences, Boulder, CO, United States
Abstract:
The Lunar Dust Experiment (LDEX) was an impact ionization dust detector onboard the Lunar Atmosphere and Dust Environment Explorer. Our current noise identification scheme allow us to unambiguously identify individual impacts from grains with radii a>0.7 um. LDEX observed a permanently present dust cloud engulfing the Moon which is non-spherical and asymmetric with respect to the direction of lunar orbital motion about the Sun, showing the highest exospheric dust densities in the 6-8 local time range. These density distributions are consistent with ejecta clouds generated from the continual bombardment of the lunar surface by sporadic interplanetary dust particles. During several of the well characterized annual meteor showers, LDEX also observed local density enhancements, especially during the Geminids. In addition to mapping out the lunar dust exosphere for large grains (a>0.7 um), LDEX was capable of searching for the putative population of 0.1 um dust grains posited to be electrostatically lofted over the lunar terminator. Throughout the mission, LDEX found no evidence for such phenomena to exist above the terminator. In this presentation, we describe the recently measured lunar dust exosphere and compare these observations with model results.
