¹I. P. Wright, ¹S. Sheridan, ¹S. J. Barber, ¹G. H. Morgan, ¹D. J. Andrews, ¹A. D. Morse
¹Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK.

The surface and subsurface of comets preserve material from the formation of the solar system. The properties of cometary material thus provide insight into the physical and chemical conditions during their formation. We present mass spectra taken by the Ptolemy instrument 20 minutes after the initial touchdown of the Philae lander on the surface of comet 67P/Churyumov-Gerasimenko. Regular mass distributions indicate the presence of a sequence of compounds with additional -CH2- and -O- groups (mass/charge ratios 14 and 16, respectively). Similarities with the detected coma species of comet Halley suggest the presence of a radiation-induced polymer at the surface. Ptolemy measurements also indicate an apparent absence of aromatic compounds such as benzene, a lack of sulfur-bearing species, and very low concentrations of nitrogenous material.

Reference
Wright IP, Sheridan S, Barber SJ, Morgan GH, Andrews DJ, Morse AD (2015) CHO-bearing organic compounds at the surface of 67P/Churyumov-Gerasimenko revealed by Ptolemy. Science 349, 6247
Link to Article [DOI: 10.1126/science.aab0673]
Reprinted with permission from AAAS