Publications by authors named "W H-P Thiemann"

The Philae lander of the Rosetta space mission made a non-nominal landing on comet 67P/Churyumov-Gerasimenko on November 12, 2014. Shortly after, using the limited power available from Philae's batteries, the COSAC instrument performed a single 18-minutes gas chromatogram, which has remained unpublished until now due to the lack of identifiable elution. This work shows that, despite the unsuccessful drilling of the comet and deposition of surface material in the SD2 ovens, the measurements from the COSAC instrument were executed nominally.

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The most pristine material of the Solar System is assumed to be preserved in comets in the form of dust and ice as refractory matter. ESA's mission Rosetta and its lander Philae had been developed to investigate the nucleus of comet 67P/Churyumov-Gerasimenko in situ. Twenty-five minutes after the initial touchdown of Philae on the surface of comet 67P in November 2014, a mass spectrum was recorded by the time-of-flight mass spectrometer COSAC onboard Philae.

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Comets harbor the most pristine material in our solar system in the form of ice, dust, silicates, and refractory organic material with some interstellar heritage. The evolved gas analyzer Cometary Sampling and Composition (COSAC) experiment aboard Rosetta's Philae lander was designed for in situ analysis of organic molecules on comet 67P/Churyumov-Gerasimenko. Twenty-five minutes after Philae's initial comet touchdown, the COSAC mass spectrometer took a spectrum in sniffing mode, which displayed a suite of 16 organic compounds, including many nitrogen-bearing species but no sulfur-bearing species, and four compounds—methyl isocyanate, acetone, propionaldehyde, and acetamide—that had not previously been reported in comets.

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More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, in the gas and solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets and meteorites and may have triggered the first chemical reactions involved in the origin of life. Ultraviolet irradiation of ices simulating photoprocesses of cold solid matter in astrophysical environments have shown that photochemistry can lead to the formation of amino acids and related compounds.

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