Mariner 9 ultraviolet spectrometer experiment: Mars atomic oxygen 1304-Angstrom emission

Selected results are presented for a considerable quantity of Mariner 9 1304-A data for the first 100 revolutions from both the bright limb and disk of Mars. The limb data suggest that the exospheric temperature is less than it was in 1969 when Mariners 6 and 7 encountered the planet. Similar (O) concentrations (0.5 to 1%) are derived for a temperature of about 300 K. Structure in the limb profiles below 200 km suggests the possibility that about 0.2 kR of the observed approximately 0.8 kR near 150 km is due to dissociative excitation of CO2. Significant differences in selected limb profiles suggest that local as well as random variations in (O) occur.