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R.E. Novak (Iona College), M.J. Mumma, M.A. DiSanti (Goddard Space Flight Center), N. Dello Russo (GSFC, Catholic University of American), K. Magee-Sauer (Rowan University), B. Bonev (University of Toledo)
Observations of Mars' atmosphere were taken at NASA's IRTF on Jan. 11-17, 2002 (Ls ~ 123 degrees) and Mar. 18-24 (Ls ~ 155 degrees). Photolysis of ozone in Mars' atmosphere by UV sunlight (Hartley bands) produces a singlet-Delta state of O2; emissions from this state (1.27 micron band) are used as a tracer for atmospheric ozone above ~ 20 km since the singlet-Delta state is quench by carbon dioxide at lower altitudes. Water is detected by observing HDO absorption bands measured near 3.67 microns. We used CSHELL (0.5 arc-sec slit width, resolving power ~ 40,000) on the IRTF for these observations. The slit was oriented north-south on Mars. In January, the slit was centered on the sub-earth point on Mars generating meridional maps at the 1.27 and 3.67 micron settings. During the March dates, the slit was stepped east-west at one arc-sec intervals for the 1.27 and 3.67 micron settings. On March 24, the slit was oriented east-west on Mars and stepped north-south. Between the two dates, column densities of HDO in the northern hemisphere substantially decreased and the detected O2 singlet-Delta emissions were more concentrated in the southern hemisphere. The 2-D maps taken in March show a decrease in singlet-Delta emissions, hence ozone column densities, between local morning and afternoon settings. 2-D maps for the 1.27 and 3.67 micron measurements will be presented along with meridional maps that compare these measurements to those of other seasons taken since 1997. This work was partially funded by grants from NASA (NAG-11398) and NSF (AST-0205397).
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.