UPPER LIMIT FOR LITHIUM IN MERCURY'S ATMOSPHERE



ANN L. SPRAGUE

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



D.M.HUNTEN

Lunar and Planetary Laboratory
University of Arizona, Tucson, AZ 85721
dhunten



F.A.GROSSE

Susquehanna University, Selinsgrove, Pennsylvania 17870




ABSTRACT

(ICARUS 123, 345-349, 1996)

High-resolution spectra of Mercury show no evidence of emission at the wavelength of the lithium resonance doublet, 6708 Angstroms. Observations were made with the 1.5-m telescope at the Catalina Observatory, near Tucson, Arizona, with the LPL echelle spectrograph and cooled CCD camera system. With an rms noise level of ~0.1% we set an upper limit for the Li vertical column abundance < 8.4x10e7 atoms/sq.cm, and the Li/Na ratio is < 5.6x10e-4.