A Search For H2o2 In The Martian Atmosphere

H2O2 has been suggested as a possible oxidizer of the Martian surface. However, this minor species has not been detected so far. An upper limit of 3 10-8 for its mixing ratio has been derived by Krasnopolsky et al. (JGR 102, 6525, 1997) for Ls = 222, corresponding to a mean abundance of 10 pr-microns. This value is within the maxi- mum (5 10-8) predicted by the 1D photochemistry model of Atreya and Gu (JGR 99, 13133, 1994). We have searched for H2O2 in the northern hemisphere of Mars, on Feb. 2-3, 2001 (Ls = 112), at a time corresponding to a maximum water vapor abundance (above 50 pr-microns at latitudes of 60-90). The Texes high-resolution grating spectrograph was used at the NASA/Infrared Telescope Facility (IRTF with a resolving power of 10^5. The northern hemisphere of Mars was mapped with a pixel size of 0.3 arcsec. Individual lines of the H2O2 nu6 band have been searched for in the 1226-1235 cm-1 range, and were not detected on individual spectra. A full analysis of the data should provide a new stringent constraint upon the H2O2 abundance on Mars.