37th DPS Meeting, 4-9 September 2005
Session 57 Moon, Mercury and Venus
Poster, Thursday, September 8, 2005, 6:00-7:15pm, Music Recital Room

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[57.03] Ion Flux onto Mercury's surface and Exospheric Asymmetries

R.M. Killen, M. Sarantos (Univ. of Maryland), A.E. Potter (NSO)

One of the outstanding questions concerning the Hermean sodium exosphere is the cause and frequency of occurrence of high latitude enhancements. We have used a Toffoletto-Hill magnetosphere model, modified for Mercury, to calculate the flux of solar wind protons and ions onto the surface of Mercury as a function of solar wind density and velocity and interplanetary magnetic field. The electric potential was computed along open field lines using the Ding (1995) potential solver. The flux of heavy ions and protons are calculated separately in order to more accurately calculate the ion-sputter yield. Helios statistics for the solar wind density and velocity and the interplanetary magnetic field at the orbit of Mercury are used to constrain the solar wind input. Ion sputter rates are calculated for several solar wind conditions. In addition to these sources, we calculate photon-stimulated desorption and meteoritic vaporization rates. The Hermean sodium exosphere is then calculated and compared with observations obtained with the McMath-Pierce solar telescope.


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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.