HR: 1340h
AN: P23A-0248    [Abstracts]
TI: Depth of Regolith Cover on Mercury's Polar Volatile Deposits as a Function of Time
AU: * Killen, R M
EM: rkillen@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742 United States
AU: Crider, D
EM: dcrider@lepvax.gsfc.nasa.gov
AF: Catholic University, Dept. of Physics, Washington, DC 20064 United States
AB: Delay Doppler images of Mercury's polar regions show strong evidence for ice in the polar craters (Harmon and Slade, 1992; Harmon et al., 2001) More recent high resolution S-band (12.6 cm) and X-band (3.5 cm radar images show that the ice deposits at the north pole are buried under an average of 36 cm of regolith (Slade et al., 2004; Harcke et al., in preparation). We have modified the model of Crider and Vondrak (2003) initially developed to study lunar ice traps, to calculate the thickness of regolith cover as a function of time. This model treats burial and removal of material from impacts of meteoroids with mass greater than 1 mg. In addition we treat ice deposition and loss by sublimation, sputtering and photon-stimulated desorption by interstellar radiation. We assume realistic values for an ice layer that would be deposited by a comet impact, and we assume continual bombardment by micrometeoritic and cometary dust. We discuss the probable timing of comet impacts at both the north and south poles of Mercury.
DE: 5400 PLANETOLOGY: SOLID SURFACE PLANETS
DE: 6200 PLANETOLOGY: SOLAR SYSTEM OBJECTS (New field)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting