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
Susquehanna University, Selinsgrove, PA 17870
University of Colorado, Boulder, CO
Lunar and Planetary Institute, Houston, TX
(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.