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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Prof. Thomas Orlando, Georgia Tech
PARTICLE-INDUCED SURFACE PROCESSES
IN THE SOLAR SYSTEM
AACP Seminar Series
Material degradation (i.e. space weathering) in our solar system is known to involve the interaction of solar-wind and magnetospheric particles (ions and electrons) with the surfaces of airless bodies. Since high energy particles create low-energy electrons, most non-thermal degradation/transformations result from the inelastic scattering of secondary electrons. Therefore, the damage is inherently due to electronic excitations and the chemical products formed are often exotic and not easily produced under normal thermal conditions. This is true for complex targets such as minerals on planet, lunar and asteroid surfaces, as well as mixed low-temperature ices on outer solar system grains or within comets.
Our experimental and modeling activities in low-energy (5-50 eV) electron and 5 keV proton induced processes on minerals characteristic of Mercury and Earthâs moon will be emphasized. Specifically, we examine i) the role of magnetospheric âtornadoesâ and electron precipitation in contributing to the formation of Mercuryâs exosphere [1], ii) the thermal removal of water [2] and the purported formation of water via solar wind impact on regoliths and iii) the oxidation and formation of some complex hydrocarbons during the irradiation of nanoscale ice films on graphitic surfaces reminiscent of interstellar grains.
[1] J. MClain, G. A. Grieves, A. Sprague, D. Schriver, P. Travinicek and T. M. Orlando, in press, J. Geophys. Res.
[2] M. D. Dyar, C. A. Hibbitts, and T. M. Orlando, Icarus, 208, 425, (2010).
For more information contact Prof. Christine Payne (404-385-3125) or Prof. Susanna Widicus Weaver (404-727-4049).
