SODIUM IN MERCURY'S ATMOSPHERE: 1985 - 1988 OBSERVATIONS

A.L. Sprague, D.M. Hunten, W. Schmitt

Lunar and Planetary Laboratory, The University of
Arizona, Tucson, Arizona, 85721
fax 520-621-4933
sprague

R.W.H. Kozlowski

Susquehanna University, Selinsgrove, PA 17870

N.M. Schneider

University of Colorado, Boulder, CO

D.A. Domingue

Lunar and Planetary Institute, Houston, TX




ABSTRACT

(ICARUS 129, 506-527, 1997)

We present new results of a large number of ground-based observations of Na in Mercury's atmosphere. We used the 1.5 m Catalina Observatory planetary telescope outside of Tucson, AZ with a high resolving power (180,000) echelle spectrograph. Observations cover a period of 1985 to 1988 with ~ 120 two-dimensional spectral and spatial images. Data have been corrected for `seeing' and are absolutely calibrated. We present our measurements and interpretations with respect to abundances and the following factors: latitude, longitude, distance from the sun, radiation pressure, thermophysical properties of the surface and subsurface, solar cycle (UV flux) and solar flare events.