A&A 435, 1181-1184 (2005)
High-resolution observations of Martian non-thermal CO emission near 10 m with a new tuneable heterodyne receiverG. Sonnabend1, D. Wirtz2, V. Vetterle2 and R. Schieder2
1 NASA Goddard Space Flight Center, Greenbelt, MD, USA
2 Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
(Received 18 November 2004 / Accepted 21 February 2005)
We present first observations with the Tuneable Heterodyne Infrared Spectrometer (THIS). This instrument developed at University of Cologne has the potential to cover the mid-infrared from 7 to 19 m. By using heterodyne techniques and an acousto optical spectrometer (AOS) as a back-end the frequency resolution achieved is better than 107 at 10 m. A tuneable quantum-cascade laser (QCL) is used as a local-oscillator (LO) and the instantaneous bandwidth supplied by the mercury-cadmium-telluride (MCT) detector and the AOS is 1.4 GHz. The system operates within a factor of two of the quantum limit. During December 2003 THIS was installed at the 1.5 m McMath-Pierce solar telescope on Kitt Peak/Arizona. Observations of molecular line features from the atmosphere of Mars were carried out. We present measurements of narrow non-LTE CO2 emission from the Martian atmosphere observed with a never before achieved frequency resolution of 1 MHz. The first analysis suggests zonal winds in the mesosphere of Mars in good agreement with model predictions.
Key words: techniques: spectroscopic -- planets and satellites: individual: Mars -- infrared: solar system
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