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[37.18] 2-Dimensional HDO Maps of the Martian Atmosphere

Y.M. Cabral, R.E. Novak, T. Dunne, A. Farrell (Iona College), M. J. Mumma (NASA's GSFC), B. Bonev (University of Toledo - NASA's GSFC)

We present two-dimensional maps of HDO column densities for opposite seasons of the year. The data were collected on March 23, 2003 (L_s ~ 155 degrees) and January 11, 2004 (L_s ~ 333 degrees). We used CSHELL at the NASA Infrared Telescope Facility (0.5 arc-second slit, resolving power ~ 40,000). The slit was positioned N-S on Mars and stepped E-W at one arc-second intervals across the planet. HDO spectral lines were detected near 3.67 \mum; a solar Fraunhofer line near 3.68 \mum was used to monitor the relative proportion between reflected sunlight and surface thermal emission. Values obtained at different slit positions were interpolated and projected onto a globe. Observations from 2003 were centered near 270 W; the map shows the Hellas basin clearly detected. The 2004 observations were centered near 190 W. These observations are part of a larger project to determine the D/H ratio by measuring abundances of HDO and H₂O across the planet.

This work was partially funded by grants from NASA’s Planetary Astronomy Program (RTOP 344-32-51-96 to M. J. Mumma) and NSF RUI Program (AST-0205397 to R. E. Novak).

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.