HR: 12:05h
AN: SA12A-08 INVITED     [Abstracts]
TI: Cosmic Ray and Solar Energetic Particle Interactions with the Surface of Mars and the Moon
AU: * Feldman, W C
EM: wfeldman@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Elphic, R C
EM: relphic@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Funsten, H O
EM: hfunsten@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Lawrence, D J
EM: djlawrence@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Prettyman, T H
EM: thp@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Tokar, R L
EM: rlt@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AB: Important factors that determine the suitability of a planetary environment to spawn life as we know it are the availability of water and the level of biologically destructive radiation near the surface. Earth satisfies both requirement with ample margin. Although Mars cannot presently support life on or above its surface because of a lack of stable water and intense fluxes of UV from the Sun, very little is known about conditions beneath its surface. A complete evaluation of the cosmic-ray and solar energetic particle-induced radiation environment near the Martian surface has not been conducted. In this talk we will present the radiation dose from neutrons between 0 and 6 MeV in the low-altitude circular orbit of Mars Odyssey, and on and just below the surface of Mars from measurements made using the Mars Odyssey Neutron Spectrometer. These doses will be compared to similar ones derived for the Moon from the Lunar Prospector Neutron Spectrometer. This dose is controlled by the water-equivalent-hydrogen content of surface soils and the thickness of the atmosphere, the dose decreases with increasing atmospheric thickness and soil water content. As a result for Mars, the dose rate is least for latitudes poleward of +55 degrees (the water content is high and the topography is low), followed closely by that at latitudes poleward of -55 degrees (both the water content and topography are high), and is highest within the Tharsis plateau where the topography is high and the water content is low.
DE: 5421 Interactions with particles and fields
DE: 6225 Mars
DE: 2104 Cosmic rays
DE: 2118 Energetic particles, solar
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting