Herschel/HIFI observations of Mars: First detection of O2 at submillimetre wavelengths and upper limits on HCl and H2O2
/ Authors
P. Hartogh, C. Jarchow, E. Lellouch, Miguel de Val-Borro, M. Rengel, R. Moreno, A. Medvedev, H. Sagawa, B. Swinyard, T. Cavali'e
and 40 more authors
D. Lis, M. Blkecka, M. Banaszkiewicz, D. Bockel'ee-Morvan, J. Crovisier, T. Encrenaz, M. Kuppers, L. Lara, S. Szutowicz, B. Vandenbussche, F. Bensch, E. Bergin, F. Billebaud, N. Biver, G. Blake, J. Blommaert, J. Cernicharo, L. Decin, P. Encrenaz, H. Feuchtgruber, T. Fulton, T. Graauw, E. Jehin, M. Kidger, R. Lorente, D. Naylor, G. Portyankina, M. S'anchez-Portal, R. Schieder, S. Sidher, N. Thomas, E. Verdugo, C. Waelkens, N. Whyborn, D. Teyssier, F. Helmich, P. Roelfsema, J. Stutzki, H. Leduc, J. Stern
/ 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.
Journal: Astronomy and Astrophysics