First results on Martian carbon monoxide from Herschel/HIFI observations
astro-ph.EP
/ Authors
P. Hartogh, M. I. Błęcka, C. Jarchow, H. Sagawa, E. Lellouch, M. de Val-Borro, M. Rengel, A. S. Medvedev, B. M. Swinyard, R. Moreno
and 41 more authors
T. Cavalié, D. C. Lis, M. Banaszkiewicz, D. Bockelée-Morvan, J. Crovisier, T. Encrenaz, M. Küppers, L. -M. Lara, S. Szutowicz, B. Vandenbussche, F. Bensch, E. A. Bergin, F. Billebaud, N. Biver, G. A. Blake, J. A. D. L. Blommaert, J. Cernicharo, L. Decin, P. Encrenaz, H. Feuchtgruber, T. Fulton, T. de Graauw, E. Jehin
/ Abstract
We report on the initial analysis of Herschel/HIFI carbon monoxide (CO) observations of the Martian atmosphere performed between 11 and 16 April 2010. We selected the (7-6) rotational transitions of the isotopes ^{13}CO at 771 GHz and C^{18}O at 768 GHz in order to retrieve the mean vertical profile of temperature and the mean volume mixing ratio of carbon monoxide. The derived temperature profile agrees within less than 5 K with general circulation model (GCM) predictions up to an altitude of 45 km, however, show about 12-15 K lower values at 60 km. The CO mixing ratio was determined as 980 \pm 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009.