Herschel/HIFI observations of Mars: first detection of O_2 at submillimetre wavelengths and upper limits on HCl and H_2O_2
arXiv:1007.1301 · doi:10.1051/0004-6361/201015160
Abstract
We report on an initial analysis of Herschel/HIFI observations of hydrogen chloride (HCl), hydrogen peroxide (H_2O_2), and molecular oxygen (O_2) in the Martian atmosphere performed on 13 and 16 April 2010 (L_s ~ 77°). We derived a constant volume mixing ratio of 1400 +/- 120 ppm for O_2 and determined upper limits of 200 ppt for HCl and 2 ppb for H_2O_2. Radiative transfer model calculations indicate that the vertical profile of O_2 may not be constant. Photochemical models determine the lowest values of H_2O_2 to be around L_s ~ 75° but overestimate the volume mixing ratio compared to our measurements.
Accepted for publication in Astronomy and Astrophysics (special issue on HIFI first results); minor changes to match published version