Letter to the Editor

First results on Martian carbon monoxide from Herschel/HIFI observations^*

¹ Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
² Space Research Centre, Polish Academy of Sciences, Warsaw, Poland
³ Environmental Sensing & Network Group, NICT, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan
⁴ LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
⁵ STFC Rutherford Appleton Laboratory, Harwell Innovation Campus, Didcot, OX11 0QX, UK
⁶ California Institute of Technology, Pasadena, CA 91125, USA
⁷ Rosetta Science Operations Centre, European Space Astronomy Centre, European Space Agency, Spain
⁸ Instituto de Astrofísica de Andalucía (CSIC), Spain
⁹ Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Belgium
¹⁰ DLR, German Aerospace Centre, Bonn-Oberkassel, Germany
¹¹ Astronomy Department, University of Michigan, USA
¹² Université de Bordeaux, Laboratoire d'Astrophysique de Bordeaux, France
¹³ Laboratory of Molecular Astrophysics, CAB-CSIC, INTA, Spain
¹⁴ Sterrenkundig Instituut Anton Pannekoek, University of Amsterdam, Science Park 904, 1098 Amsterdam, The Netherlands
¹⁵ LERMA, Observatoire de Paris, France
¹⁶ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
¹⁷ Bluesky Spectroscopy, Lethbridge, Canada
¹⁸ SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD, Groningen, The Netherlands
¹⁹ Leiden Observatory, University of Leiden, The Netherlands
²⁰ Joint ALMA Observatory, Chile
²¹ Institute d'Astrophysique et de Geophysique, Université de Liège, Belgium
²² Science Centre, European Space Astronomy Centre, European Space Agency, Spain
²³ Department of Physics and Astronomy, University of Lethbridge, Canada
²⁴ Physikalisches Institut, University of Bern, Switzerland
²⁵ KOSMA, I. Physik. Institut, Universitat zu Köln, Zülpicher Str. 77, D 50937 Köln, Germany
²⁶ Osservatorio Astrofisico di Arcetri-INAF, Largo E. Fermi 5, 50100 Florence, Italy
²⁷ Jet Propulsion Laboratory, Caltech, Pasadena, CA 91109, USA
²⁸ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D53121 Bonn Germany

Received: 5 June 2010
Accepted: 6 July 2010

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 ¹³CO at 771 GHz and C¹⁸O and 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 ± 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009.