This contribution focuses on two aspects of our work, which relate to an analysis of refractory residues formed from UV irradiation and warming of astrophysical ice analogs, the RAHIIA project and for the other a new project that we are  eveloping and aims to the volatile organic compound analyses coming from the warming of these analogues, the VAHIIA project. The understanding of the formation of refractory residues, commonly called 'Yellow Stuff' is an important step to  establish what kind of organic matter could be available within interplanetary objects such as comets or asteroids, and therefore available for the development of a prebiotic chemistry on the surface of terrestrial planets. We present here the first results obtained by spectrometric analysis with high resolution mass spectroscopy (LT-Orbitrap) of these residues. These analyzes show that these residues are composed of ten of thousand of molecules of high molecular weight(m / z> 4000), and present an average elemental composition H/C = 1.6, N/C = 0.4, O/C = 0.4 for an initial ice containing H2O:CH3OH;NH3 3:1:1. In addition, this type of analyses allows the search of specific molecules. We identified various derivatives of hexamethylenetetramine (HMT), which confirms previous observations. These results demonstrate that from only three simple molecules CH3OH, H2O and NH3, a complex chemistry occurs when these molecules are subjected to physical processes available in astrophysical environments. A discussion on this complex astrophysical chemistry will be discussed. In a second part, we present the first results of the VAHIIA project that will provide more information on molecules that sublimate during the heating of cometary grains as well as in hot cores, and will give information for a better understanding of the chemical processes responsible for the formation of refractory residue.[1]  Characterization of interstellar/cometary organic residue analogs using very high resolution mass spectrometry, G. Danger, F-R. Orthous-Daunay, P. de Marcellus, P. Modica, V. Vuitton, F. Duvernay, L. Le Sergeant d'Hendecourt, R. Thissen, and T. Chiavassa, Geochimica & Cosmochimica Acta, 2013, 118, 184-201.[2]  Importance of thermal reactivity for hexamethylenetetramine formation from simulated interstellar ices , V. Vinogradoff, N. Fray, F. Duvernay, G. Briani, G. Danger, H. Cottin, P. Theul� and T. Chiavassa, Astronomy and Astrophysics, 2013, 551, A128.

Analyses of volatile organic compounds and organic refractory residues coming from the heating of cometary/interstellar ice analogs: An insight in complex astrophysical chemistry

247th National Meeting (2014)

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